Session management for OS X

This patch aims to implement the session management available on OS X.
Currently applicationShouldTerminate is just a go through that closes
everything and ends the application. The new implementation calls
first appCommitData and cancels the termination properly if required.
This means that if a user wishes to logout, Qt applications can now
cancel that like e.g. answering to Safari asking whether it is ok to
close because of a number of opened tab/window.

Task-number: QTBUG-33034
Change-Id: Icedc8590a1c0934d9bc87d3a43d6702a9903bfb8
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Android: New bearer plugin

Replacement for the the generic bearer plugin.
Compared to the generic bearer engine, this plugin provides a more
detailed overview of the network configurations on Android.

Added features are:
- Correct bearer type, also for mobile connections.
- Connection state (e.g., roaming).
- Data statistics (On devices that supports it).
- Polling is not required.

Change-Id: I728cb91e04a66343648c0add6be2a003caca0f1f
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>