Move to a middleware scheme

This allows much tighter integrations with frameworks
Refactor all the things
Improve middlewarez
Set context and user data in django [Fixes #10] [Fixes #17]
Send projectRoot and libRoot for debugging [Fixes #15]
Default to development if debug mode is on [Fixes #19]
Fix python2.6 support
Don't send KeyboardInterrupt to bugsnag
Read query params, but not forms [Fixes #24]

In order to do this we'd have to reset wsgi.input, which can't be done
in any particularly nice way.
Add some tests for flask integration
run tests on 3.3
update docs
TYPO
Document before notify
truncate strings only if payload is too long [Fixes #26]
Remove obsolete check for development
Fix json_encode on python 3
move Http404 into default ignore classes

Makes it easier to remove
Merge branch 'middleware'