Support for Ubuntu 12.04

There are two main changes here:
1) includes in Property.h, GLMesh.h, and SDLSys.cpp
2) cmake compatibility with FindGLEW.cmake and a check for c++0x
moved new includes to header

SDLSys.cpp had <iostream> and <cstring>; they are now in SDLSys.h
Merge pull request #13 from wrongu/develop

Ubuntu 12.04 support