Remove unused imports and minor corrections.
Adds google.py -- a plugin for google searches and google image searches.
Remove class docstring comment at example module docs

I found myself to be constantly re-iterating on the same
 thing that has been said in the top-of-file docstring description
 that it's rather redundant to have a class docstring.

Should you feel your specific module still requires one,
 then you're still free to add your own. It's just silly
 to have it as default though.

This also removes redundant docstrings in current modules.
Fix a mismatching variable name in ratelimit.notice.
Convert all modules to use 'target' in favor of 'channel'

Channels are not always the target, maybe the user performs
 a command from within PM. Then the reply_channel method will be
 misleading. All instances of channel have been replaced with
 'target'. This includes method names, so reply_channel
 has become reply_target(target, nick, "response")
PEP8