New `models.Comment()` object, `Post()` can now fetch comments
Some refactoring in Notification model and streams
pydoc will now correctly read doctsing for diaspy/streams.py,
Post().delete_like() now returns error code on success
Err, it was kinda stupid to return anything about *deleted* stuff,
removed it
Imporved error message in diaspy.streams.Stream()._photoupload()
Initiali work on retrieving languages list
Merge branch 'devel' into settings
You can now get list of languages in settings