Cedar-backup3

* Change writeIndicator() to raise exception on failure (closes 53).
* Change buildNormalizedPath() for leading "." so files won't be hidden
* Remove bogus usage of tempfile.NamedTemporaryFile in remote peer.
* Refactored some common action code into CedarBackup2.actions.util.
* Add unit tests for a variety of basic utility functions (closes: 45).
- Error-handling was improved in some utility methods
- Fundamentally, behavior should be unchanged
* Reimplement DVD capacity calculation (initial code from Dmitry Rutsky).
- This is now done using a growisofs dry run, without -Z
- The old dvd+rw-mediainfo method was unreliable on some systems
- Error-handling behavior on CdWriter was also tweaked for consistency
* Add code to check media before writing to it (closes: 5).
- Create new check_media store configuration option
- Implement new initialize action to initialize rewritable media
- Media is initialized by writing an initial session with media label
- The store action now always writes a media label as well
- Update user manual to discuss the new behavior
- Add unit tests for new configuration
* Implement an optimized media blanking strategy (closes: 48).
- When used, Cedar Backup will only blank media when it runs out of space
- Initial implementation and manual text provided by Dmitry Rutsky
- Add new blanking_behavior store configuration options
- Update user manual to document options and discuss usage
- Add unit tests for new configuration

* Fix typo in new split section in the user manual.
* Fix incorrect call to new writeIndicatorFile() function in stage action.
* Add notes in manual on how to find gpg and split commands.

* Fix some encrypt unit tests related to config validation
* Make util.PathResolverSingleton a new-style class (i.e. inherit from object)
* Modify util.changeOwnership() to be a no-op for None user or group
* Created new split extension to split large staged files.
- Refactored common action utility code into actions/util.py.
- Update standard actions, cback-span, and encrypt to use refactored code
- Updated user manual to document the new extension and restore process.

* Fix log message about SCSI id in writers/dvdwriter.py.
* Remove TODO from public distribution (use Bugzilla instead).
* Minor changes to mbox functionality (refactoring, test cleanup).
* Fix bug in knapsack implementation, masked by poor test suite.
* Fix filesystem unit tests that had typos in them and wouldn't work
* Reorg user manual to move command-line tools to own chapter (closes: 33)
* Add validation for duplicate peer and extension names (closes: 37, 38).
* Implement new cback-span command-line tool (closes: 51).
- Create new util/cback-span script and CedarBackup2.tools package
- Implement guts of script in CedarBackup2/tools/span.py
- Add new BackupFileList.generateSpan() method and tests
- Refactor other util and filesystem code to make things work
- Add new section in user manual to discuss new command
* Rework validation requiring least one item to collect (closes: 34).
- This is no longer a validation error at the configuration level
- Instead, the collect action itself will enforce the rule when it is run
* Support a <no_eject> flag in store configuration (closes: 39).
- Change StoreConfig, CdWriter and DvdWriter to accept new flag
- Update user manual to document new flag, along with warnings about it
* Support repository directories in Subversion extension (closes: 46).
- Add <repository_dir> configuration modeled after <mbox_dir>
- Make <type> configuration value optional and for reference only
- Refactor code and deprecate BDBRepository and FSFSRepository
- Update user manual to reflect new functionality

* Fix a few places that still referred only to CD/CD-RW.
* Fix typo in definition of actions.constants.DIGEST_EXTENSION.

* Add support for DVD writers and DVD+R/DVD+RW media.
- Create new writers.dvdwriter module and DvdWriter class
- Support 'dvdwriter' device type, and 'dvd+r' and 'dvd+rw' media types
- Rework user manual to properly discuss both CDs and DVDs
* Support encrypted staging directories (closes: 33).
- Create new 'encrypt' extension and associated unit tests
- Document new extension in user manual
* Support new action ordering mechanism for extensions.
- Extensions can now specify dependencies rather than indexes
- Rewrote cli._ActionSet class to use DirectedGraph for dependencies
- This functionality is not yet "official"; that will happen later
* Refactor and clean up code that implements standard actions.
- Split action.py into various other files in the actions package
- Move a few of the more generic utility functions into util.py
- Preserve public interface via imports in otherwise empty action.py
- Change various files to import from the new module locations
* Revise and simplify the implied "image writer" interface in CdWriter.
- Add the new initializeImage() and addImageEntry() methods
- Interface is now initializeImage(), addImageEntry() and writeImage()
- Rework actions.store.writeImage() to use new writer interface
* Refactor CD writer functionality and clean up code.
- Create new writers package to hold all image writers
- Move image.py into writers/util.py package
- Move most of writer.py into writers/cdwriter.py
- Move writer.py validate functions into writers/util.py
- Move writertests.py into cdwritertests.py
- Move imagetests.py into writersutiltests.py
- Preserve public interface via imports in otherwise empty files
- Change various files to import from the new module locations
* More general code cleanup and minor enhancements.
- Modify util/test.py to accept named tests on command line
- Fix rebuild action to look at store config instead of stage.
- Clean up xmlutil imports in mbox and subversion extensions
- Copy Mac OS X (darwin) errors from store action into rebuild action
- Check arguments to validateScsiId better (no None path allowed now)
- Rename variables in config.py to be more consistent with each other
- Add new excludeBasenamePatterns flag to FilesystemList
- Add new addSelf flag to FilesystemList.addDirContents()
- Create new RegexMatchList class in util.py, and add tests
- Create new DirectedGraph class in util.py, and add tests
- Create new sortDict() function in util.py, and add tests
* Create unit tests for functionality that was not explictly tested before.
- ActionHook, PreActionHook, PostActionHook, CommandOverride (config.py)
- AbsolutePathList, ObjectTypeList, RestrictedContentList (util.py)