Revamps the config system.

This removes the need to import config:
1. from the backends (the config is passed to the constructor)
2. more importantly from the plugins

From a plugin you can access it with:
self.bot_configuration

This is straight the module at the moment.
bot_config and test fixes
pep8
tests fix
pep8
trailing space ...
Merge branch 'master' into errbot-config

Conflicts:
	errbot/backends/graphic.py
	errbot/backends/text.py
Merge pull request #314 from gbin/errbot-config

Revamps the config system.