Added TaskAttachment data model
Added all the boilerplate for task attachments--outstanding daos, integration with messages, etc.
Forgot to add dao files
Removed and updated all references to FileMetadata to use new TaskAttachment
Deprecated and removed unecessary fields from FileMetadata
Wrote a migration from FileMetadata to TaskAttachment
Record file attachment outstanding entries and report them using special ChangesHappened logic
Fixed duplicate column name in TaskAttachment
Fixed several bugs/missing pieces that were preventing task attachments from syncing
Fixed file uploading (use JSON instead of string), make sure that EditNoteActivity has Task.PUSHED_AT
Merge remote-tracking branch 'origin/130208_sb_task_attachments' into 130122_sb_new_sync