gestures: use transparent window instead of grab function

gestures: use transparent window instead of grab function

This path removes the grab functionality from screen reader
due to some undefined behaviour it caused to EFL input processing.
The grab caused X11 internal devices hierarchy changed and EFL
is not properly updating and adjusting input processing to this changes.

Patch adds input window which will capture all input from screen.
Input window will be raised every time the _NET_CLIENT_LIST_STACKING
property changes on root window.

Change-Id: Ic961520772d84b6a3491ba62c292d7780666960c