Qt5build

(after release?)

this patch enables building against qt5 (by default in /opt/qt5). usage:

       source scripts/setenv-unibuild.sh qt5
       qmake && make

qt5 features that may be useful in the future:

1. ability to run without X (raspberry Pi, cellphones, etc)

2. built in GUI testing framework that can simulate GUI actions

3. modular - only need to ship the parts of QT that are actually used (this can help reduce binary package size for Windows, Mac, and Linux)

Bugs: 

It builds and runs, but on my machine, ubuntu 12.04, the OpenGL window has severe 'lag' between mouse input and rotation.