Refactor the input framework

Refactor the input framework

Results of the ongoing workshop in Oslo:
QInputPanel will be the application facing interface
for controlling the input context as well as querying
things like the position of the virtual keyboard.
QInputContext is significantly cleaned up and only there as
a compatibility API for existing code.

Change-Id: Ie8e2ee480930763f414bfaae63247b1fb6500c82
Reviewed-on: http://codereview.qt.nokia.com/4357
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Vesa Rantanen <vesa.rantanen@nokia.com>
Reviewed-by: Joona Petrell <joona.t.petrell@nokia.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>