Fix test_edit_handlers breaking other tests
Update snippets tests

Add an Advert fixture so that Advert objects do not need to be created
by the tests that use them.
Merge branch 'master' into fix-edit-handlers-test

Conflicts:
	wagtail/wagtailadmin/tests/test_edit_handlers.py
Merge branch 'master' into fix-edit-handlers-test

Merge. Remove deprecated tests.

Conflicts:
	wagtail/tests/fixtures/test.json
Fix wagtailsnippets.tests.TestSnippetChooserPanel

Fix wrong argument type passed to SnippetChooserPanel
Removed EditHandler tests. Added more FieldPanel tests
Merge branch 'master' into fix-edit-handlers-test

Conflicts:
	wagtail/wagtailembeds/tests.py
Tweak FieldPanel tests
Merge branch 'master' into fix-edit-handlers-test
Fix FieldPanel test failures
Remove mock expected calls from edit handler tests

'Expected calls' works differently in Python 2 and 3
Merge pull request #363 from mope/fix-edit-handlers-test

Tidy up unit tests