Removing deprecated callback return statements

this raises deprecation warnings and causes an
undesired behaviour in publisher where the modal
doesn't close upon failure, fixed that.

http://fuelyourcoding.com/jquery-events-stop-misusing-return-false/
Renaming variables to convey intent better
Don't submit edition form if its not dirty

This was causing an unnecessary POST request
to be sent to the server, and an undesired
side-effect in the scheduled publishing
workflow.
Disabled forms & actions when scheduled
Integration test
Sensible retry logic for scheduled publishing
Make enhancements eager_load! friendly
Using govuk_content_models with scheduling changes
Update statsd stats