Fix tests after changes introduced by #86
Merge pull request #93 from dulaccc/fix-changed-by-not-set

Fix tests after changes introduced by #86 Thank you
Improve the image diff layout with a little css
Fix image diff tests
Merge pull request #94 from dulaccc/enhance-admin-layout

Improve the image diff layout with a little css. Thank you @dulaccc
Add a Makefile for convenience on running pep8 tests
Add the venv usual directory to avoid adding the virtualenv to the repo
Replace the EmailThread by backend classes that are switchable

currently only support the synchronous email backend
Add some explanations to the README file
Add missing test for custom message backends
Fix the pep8 warnings
Merge pull request #90 from dulaccc/message-send-backends

Should we prefer celery tasks rather that threads. Thank you