- pretty-print output command list (e.g. 'list-all')
- add dewi.utils.archive, which contains an UnZip class to (partially) unzip
.zip files
- if a command is mistyped or non-existing, print at most 6 similar command
names, or list all of them
- dewi.images.filedb: add rollback() method to FileDatabase
- dewi.core.context: Context got 'commands' and 'command_registry'
properties, and always contains the corresponding 'commands' and
'commandregistry' fields
- introduce dewi.core.logger module, log_debug, log_info, etc. can be used