Add unit tests for edit_handlers.py. Lint edit_handlers.py.
Merge branch 'master' into edit-handlers-unit-tests

Conflicts:
	wagtail/wagtailadmin/edit_handlers.py
Remove broken test
Update edit handlers unit tests

Add more tests. Clean up modified class properties after tests finish.
Replace assertRegexpMatches with assertIn.
Merge branch 'master' into edit-handlers-unit-tests
Fix Travis test failures
Reorganise unit tests to obviate the use of del
Merge pull request #335 from mope/edit-handlers-unit-tests

Add unit tests for edit_handlers.py. Lint edit_handlers.py.
Revert "Merge pull request #335 from mope/edit-handlers-unit-tests"

This reverts commit 7ad6be82f3913893dcd82dd2af904da4c654c3ff, reversing
changes made to 4c77a4b18a8fef9abd3bcc1fccaf5627f1604522.
Alter comment formatting in wagtailcore tests.py
Merge branch 'master' into rich-text-unit-tests