CMake standalone on Mac

After compiling CAFCore on Mac with CMake standalone, QFramework cannot be imported in an interactive python session. The problem is that DYLD_LIBRARY_PATH (which seems to be the Mac equivalent of LD_LIBRARY_PATH) is always reset when a new shell/process/something is started (ask @cburgard for details).

A solution is to add the paths to the variable when the framework is initialized (instead of setting it in cafcompile.sh).