kconfig qconf: port to QT4

A straight forward port to QT4 using qt3to4 and compiling against
  qt3support

* Use pkg-config to detect QT4 which is hopefully portable enough
* If no QT4, QT3 will by tried instead
* Classes renamed using qt3to4
  * If build using QT3 renamed to QT3 class names using defines
* ConfigInfoView::menu has to be renamed as QT4 moc strips struct from
  struct menu and creates a name conflict
* QT2 support has been dropped
* The hidden options inserted in 39a4897c
  are use in native API

Signed-off-by: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>