Pybbm

* Fast fix for migrations for Posgres database.
If you already get and applied migrations from 0.17 version (for example on MySQL DB) you can skip new
migrations with `manage.py migrate pybb --fake`

* Topic and post creation wrapped in transaction
* All topic/post/poll related forms can be overrided when custom view inherites pybbm view
* Demo data for example projects
* Using active markup engine when quoting posts via javascript
* Functionality to support disabling default pybbm subscriptions and notifications and
new settings: `PYBB_DISABLE_SUBSCRIPTIONS` and `PYBB_DISABLE_NOTIFICATIONS`
* Fixed sorl.thumbnail/easy_thumbnail compatibility in standard `pybb/avatar.html` template
* Improved example projects
* Removed applying `urlize` filter over html produced by markdown parser
(it doesn't play nicely with html markup as noted in django's docs)
* django 1.8 compatibility
* common django layout for test project
* use mysqlclient package for testing installation with mysql database backend on python 3
* optional enabling "nice urls" for entire forum,
that looks like '<forum prefix>/c/<category slug>/<forum slug>/<topic slug>/'

* Fast fixes

* Django 1.7 compatibility.
* Fixed creating custom profile model of any class defined in settings with right related name to user model.
*Migration note*: If you have workaround for creating profile in your code, you should remove it for
preventing possible dubplicate unique key error on user creating.
* New get_display_name method for profile model used to unification displaying username through forum
* New markup processing. See `markup`

* Make all migrations compatible with custom user model. Break dependency on sorl.thumbnail in migrations
* Compatibility functions moved to compat.py module
* Email notifications optimization
* Example_bootstrap projects now based on bootstrap 3
* Fixes and improvements

* Fixed bug when user can vote (or cancel vote) when topic was closed.
* Added `may_vote_in_topic` method to permission handler.
* Fixed blocking user view