Corrected bug https://github.com/haiwen/seahub/issues/212 - unnecessary
mandatory params in Unshare a library web API
Implemented the directory rename web API
Multiple user (separated by comma) in the user field can be used to a
personal share of a library. 
The same permission applies to all this users.
If an error occurs a unshare rollback is done for all already shared
users.
Merge branch 'master' of git://github.com/bits4beats/seahub into bits4beats-master
[api2] Refactor dir rename and library share/unsahre
Merge branch 'bits4beats-master'