Using "SDL2/SDL_xxx.h" instead of "SDL_xxx.h" caused
the include paths provided by pkg-config to be ignored,
and headers from a standard include path to be used instead.
This should make graphics.cpp somewhat easier to navigate/read.
GL_EXT_timer_query is also made optional, and if it's not present
dummy functions will be called instead.
The drawing is now completely shader based, which makes away
with all usage of the depracted matrix stack. This also allows
us to do things like simple translations and texture coordinate
translation directly instead of doing everything indirectly
through matrices.
Fixed vertex attributes ('vertexPointer()' etc) are also
replaced with user defined attribute arrays.
Prevents a distorted screen when an error happens during
script loading (ie. before the first drawn frame) and fullscreen
is turned on in the config.
This will also be necessarry once fixed aspect ratio is implemented.
Jonas Kulla