Patches for QT 5, VS 2012 and more fixes on VTK 6 over #218

The QT 5 fixes are from https://bitbucket.org/manctl/pcl/commits/095d858dd4f843ecfa637708d25a5202467f44d1, with a work around for QT bug 29331: https://bugreports.qt-project.org/browse/QTBUG-29331.

More fixes on VTK 6 are made following pull request #218. The support for CUDA 5.5 is also added.

These patches do not change any algorithm.