Fix vs2012 proj generator etc

Hey Leo, 

this PR fixes the project generator for VS2012… it's also addressing the strange fstream crash issues that happened when testing the project generator…

Let me know if that works for you!

Cheers
#
Tim

* The project generator project file was originally *not* properly
linked against MultiThreadedDebugDLL, which lead to extreamly misleading
crashes when closing derived fstream and istream classes, because
debugging is more interesting that way...

it has something to do with how the system libraries are laid out, I
came to believe.

<RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>

was the big game changer.

* also adds missing GUI elements for ofxGUI in project Generator Project
file.