This commit reactivate unit testing in SFLphone android.
Tests are trivial for now, but will contribute in setting up the whole
testing process with jenkins.

The main issue here is due to the build system of the stack compared to a pure Android
NDK project. Generating arm and x86 ABI at the same time does not seem to be possible.

There is an issue in a UI element (ViewPager), which does not get properly populated
when restoring its state. (found using VMs with API=16)

Home interface now only have one list to display conferences (renamed conversations)
There are still some issues with conference mapping client side.

Android contact id is retrieved from the history database, and is linked to the
history view.

History is now stored in a lightweight ORM database.
Corners cases are still not treated, but simple calls are saved properly.

Every call is considered has a Conference, holding one or several SipCall.
This simplify extraction and storage of calls in history. It also provide a unique interface
to handle calls instead of two (which were SipCall and Conference).

This commit also fixes minor indent errors and remove unused class
AnimationManager.

We now have a feedback on wifi strength during a call in application log.
Some testing should be done but it seems reliable.
It should be integrated in the user interface in the future.

Issue was caused by retrieving the wrong reference on the displayed screen.

sflphone module