Examples: several fixes for text

* Cut/Copy/Paste works
* The initial status for b/i/u and alignment works
* Font size and family works
* Text color works

Task-number: QTBUG-31482
Change-Id: I299931dede9defbb1d3eb927f867e77d20ded5ae
Reviewed-by: Caroline Chao <caroline.chao@digia.com>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>