QtIFW

Add some useful information about the installer base version.

Add the git sha1 and the build date to the verbose output, seems
more useful then the static version 2 we had before. Add --version
command line paramter. Small changes to the verbose output.

Change-Id: Idce7025dd64f3d56c2e6c53408167c95f41040d4
Reviewed-on: http://codereview.qt-project.org/5863
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Tim Jenssen <tim.jenssen@nokia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@nokia.com>