Merge pull request #10 from chriadam/master

[nemo-qml-plugin-social] Ensure Facebook data cache integrity
Added support for sections

This commit provides a new role in SocialNetworkInterface,
"section", that can be passed to ListView.section.property.

Providing "section" properties should be done for subclasses
of SocialNetworkInterface, by implementing
SocialNetworkInterface::dataSection, for relevant data types.
Merge pull request #9 from SfietKonstantin/section

Added support for sections
Fix QML warnings in tests
Permits "me" to be identified

This commit retrieve the Facebook identifier associated to the
generic "me" identifier, and reuse it to perform calls involving
"me", and using the cache system instead of allocating new nodes
all the time.
Merge pull request #11 from SfietKonstantin/tests

Small cleanups for the tests