Merge pull request #25 from SfietKonstantin/master

[nemo-social] Bugfixes to model functionality
[bugfix] Permits the current user to be identified

This commit provides a nicer way to detect the current user
for Facebook. When the user first query Facbeook, if the
current user is not loaded, it will perfrom a double query
to load the current user identifier in the same time.