Fix a bug for a user is connected with more than one socket on the same frontend.
On disconnect the module originally remove the record from persistence for this user@frontend.
Add a test to check if at least another session remain for this user@frontend before record deletion.
.gitignore
Add a getStatusByUid method, shortcut to obtain directly a boolean value of the status (online or not) of the given user.
Add a getStatusByUids method, shortcut to obtain directly statuses list for several users in one request.
Merge pull request #9 from dbrugne/master

Bug fix for multi-device/session users on the same frontend and add getStatusByUid and getStatusByUids methods