Fixed|ClientWindow|Windows: No need to recreate GL Canvas for FSAA/vsync changes

FSAA is handled by multisampling the GLTarget renderbuffers, so there
is no need to touch the window surface. Also, changing vsync is done
via a WGL extension API.

Fixes the issue with weird GL behavior when FSAA or vsync is toggled.
Merge branch 'master' of ssh://github.com/skyjake/Doomsday-Engine
Fixed: Various build errors and warnings

Not many legitimate problems here, mostly warnings/errors due to
stricter implementation of the C++11 standard.