Added copyright note for OOF module
Fix the SIEVE script when it was enabled/disabled

This happened when you enable OOF to all people and then you disable it.
Merge branch 'master' into ejhernandez/oof-managesieve
Refactor to make possible to have several backends to put the Sieve script
Make it work with curl for easing the testing
Now it is working if there is already an active script
ManageSieve backend for Out-of-Office implemented
Keep the user_script in settings file

It helps to keep the user script among different Set requests on OOF
Make multitenancy work checking the samba conf key
Fix getting the param properly

It does not use the standard get from dict
Fix in ManageSieve backend when there is no active script
Settings are stored in the script inline

* Log on errors to ease troubleshooting
* Avoid making openchange node stateful
Minor changes after proper review

* Add myself to copyright
* Use debug instead of info level in some messages
Merge pull request #85 from sixstone-qq/ejhernandez/oof-managesieve

Out-Of-Office supports ManageSieve backend