Improve DovecotTesting
- replace SetupEnvironment.sh by a node script, allow us to know which mode we are in
- add a script to change the UID validity of one mailbox for testing
- install the env in Travis before lauching tests (less risk of timeout)
add level-based logging
Implement write actions + tests
Fix handling of uidvalidity changes + test
Travis fix
test fix
switch to UUID & bugfix
remove debug logging
remove wrong test
add route for attachments
 + bugfix : binaries were lost on message update
Merge pull request #33 from aenario/master

Implement write actions
Merge branch 'master' of https://github.com/cozy/cozy-emails

Conflicts:
	package.json
	server/controllers/messages.coffee