Removed NetBeans-clutter from the repository

Added a .pro-file to allow for building the application from the
commandline using qmake.
Fixed a few header paths in the .ui files that I forget before.

Now a complete "make clean; qmake; make release" runs smoothly.
Added routines for checking the applicability of group assignments and
ranking information to categories.

Added methods to get the group assignments from the group assigment
widget.

Preparational commit for later merging with "master".