[win32][added] Hybrid shutdown on Windows 8
Merge pull request #2578 from a11599/hybridshutdown

[win32][added] Hybrid shutdown on Windows 8
fixed, a) space monster running wild, b) += monster running wild, c) using -std=gnu99 in platform_cxxflags, d) remove -Wl,-search_paths_first from darwin, no required and spews all over the place
fixed, missed one in previous commit
[WIN32] removed m_AppActive and use SetRenderGui instead.
Merge pull request #2546 from wsoltys/setrendergui

changed: removed m_AppActive in favor of SetRenderGUI()