Thumbnail loading fix. Loading the same thumbnail twice fixed.
Merge pull request #83 from zchydem/master

Bugfix for loading the same image/thumbnail twice caused loading error.
Add 'enabled' role to AccountModel
Merge pull request #86 from blammit/enabled-role

Add 'enabled' role to AccountModel
Allow arbitrary requests to be performed via SocialNetwork

This allows clients to perform some request to, for example, retrieve
the identifier of some graph object that they wish to set as the node
in the model, without going through multiple request round trips.