Some improvements for xrandr

- choose best available refresh rate
 - if resolution doesn't exist, choose first available
 - other minor changes.

Works fine with Gnome, but I notices some issues on Openbox and Unity.
Try to replace emplace_back() call.

Only on some part of the code, need confirmation it works before
propagating.
If there is a sphericalHarmonicsTexture, kill ambient.
Force billboard to render in transparent phase, won't work otherwise
Rename cpp2011.h
Fix include in stkbillboard
Remove  some other emplace_back.
Fix include in wiimote_manager.hpp
Fix c++2011 logic from previous commit. STK now builds again on my mac, finally!
In artist debug mode, fast-track race start even more, tired of waiting after thunderbird to test
Remove ambient

It's already added in the diffuse env pass
Update doxygen comment.
Port instancing shaders to singleton.
Try a fix for intel and kart selection screen.
xrandr: fixed issue with fullscreen window which was placed in wrong screen in some window managers.

In some cases main screen may have other position than (0, 0) - fixed it.
xrandr: now it seems to work fine. I enable it for testing.

This should be useful for people which have two or more display devices. It changes resolution only on main screen and leaves other screens untouched.

Currently I use screen which is the most on left (or on top). Ideally we should be able to choose in settings which screen we want to use. But support it on all platforms is rather too much of work. We could also detect from which screen STK was executed. This can be done differently on different window managers, but nothing impossible. Maybe in future.

Perhaps we should add fallback using old xrandr method.

BTW. in some specific cases it works better than SDL2 ;-)
Applied konstin's bugfix for an editor crash.