update .gitignore to play nicely with django
django bridge to current schema
#424 deduplication script implemented as a manage.py command, with tests and fixtures
tatoeba2-django: add missing HOST db config in settings template
#424 handle merging tags
#424 handle merging lists, favorites, and annotations
#424 switch comment merging from updating records to copying records
#424 handle merging logs by copying records
 #424 remove extra comments from fixtures and assert total counts in comment merging test
#424 add new merge functions to main deduplication transaction
 #424 add a logging framework for the script with tests, covers stdout, string, and file streams. also moved link logging to json serialization on file stream.
#424 add json file logging to all operations
#424 refactored merging code into two abstract types: insert merging and update merging. all tests still pass.
#424 all operations are logged to stdout and string stream. also, added options to dump string stream to the wall and post comments on merged sentences
tatoeba2-django: updated requirements.txt for new features in dedup script
#424 ram optimization for full scan deduplication + minor improvements to report messages + fix for duplicate verbose option
#424 few fixes: NAME setting, unmanaged models handle primary key on lists table, bot is bound to Dedup instead of Command
#424 added dry run with a simple test
in the favorites_users table.
 #424 more fixes: insert merge supports complex filtering, merges on the contributions table is tightly filtered and tightly tested, deletion logging obeys dry run option, datetime objects are all timezone aware, and useless DATABASE setting removed