Adapt to the input method changes in qtbase

Adapt to the input method changes in qtbase

Start using the QInputPanel instead of the QPlatformInputContext.
Make sure we do something with both QInputMethodEvent and
QInputMethodQueryEvent. This gets input methods partially
working on TextInput fields.

Change-Id: I4655f5599673325ffb75207573635afccd069a65
Reviewed-on: http://codereview.qt-project.org/4404
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Vesa Rantanen <vesa.rantanen@nokia.com>
Reviewed-by: Andy Nichols
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>