Velociwrapper

- Better PEP-8 complience (not 100% complete yet)
- added VWBase.collection() which returns a defined collection
for a model or a new base collection if one isn't defined.
- fixed VWBase.more_like_this() not working (collection.py has been merged
with base.py)
- other minor fixes

- first public release
- fixed version numbers

- consolidated version number
- fixed a bug in callbacks
- fixed bool type only accepting integers
- fixed _create_obj() being called multiple times
- fixed collection generator crash when a document has no _source

- rewrite of much of the internal query system
- created qdsl.py module to output parts of Query DSL by calling functions
- created querybuilder class that uses the QDSL functions and represents
the internal query state
- much easier to chain calls together
- no longer has to traverse the tree of JSON/dictionary to find where
to place new arguments
- all search methods (in collection.py) now use the querybuilder / qdsl
- Created VWCollectionGen generator object which is now returned by all()
and get_in()
- vastly improves performance on large queries
- items in the generator can still be referenced by index
- added callbacks / events
- several built-in events
- events can be added and triggered
- global event / callback system. Callbacks added to models exist for
all models of the same type

- fixed body not being propertly specified on reindex(). Caused explicit
mapping to be deleted

- added multi_match()