Allow use of a custom json encoder class.
Check parameters with regexps, escape channel name
Stringify parameters early
Support upper case channel names
Merge remote-tracking branch 'onyxfish/master'

Conflicts:
	README.md
	pusher/__init__.py
The default encoder should be None
Edited the README
Merge branch 're_and_escape'
Fixed tests
Minor syntactic changes
Changed Channel.trigger to expect 200 OK
allowing 200/201/202 on trigger event to accommodate slanger bug