Add testing framework to LayoutLib. [DO NOT MERGE]

This change adds an end to end test which loads the framework resources
and a test app and ensures that no exceptions or warnings are thrown.

The change also adds project configuration for intelliJ.

Change-Id: I7b67c0f1a2af2dac95df7f3231cab537b9826d7d
(cherry picked from commit a8e9517470869fa29946ae1fa1ceeb24c7970391)