Channel Quotes and User Quotes module

This pull request adds the modules `bones.modules.quotes.ChannelQuotes` and `bones.modules.quotes.UserQuotes`, which should be pretty self-explainatory.

Database structure creation will come in a later version, for now you'll have to create the tables by hand by looking at the objects in the `bones.modules.quotes` module.

PostgreSQL is the only officially supported DBMS.