Fix initial window position being top left
Free bot client if cannot load bot

Introduced by commit a57a5cfd9b5dcc51696777c67b275c55c5b4b452.
Various fixes from Fuma
#5979: Cubemap support for opengl2.
OpenGL2: Use RGBM instead of RGBE encoding for lightmaps.
OpenGL2: Fix inaccurate RGBM calculation.
Merge branch 'master' into sdl2
Fix building sdl2 branch on travis-ci

Install libsdl2-dev from a PPA.
Merge remote-tracking branch 'ioquake3/sdl2' into sdl2

Conflicts:
	.travis.yml
	code/game/g_bot.c
	code/renderergl2/tr_backend.c
	code/renderergl2/tr_bsp.c
	code/renderergl2/tr_local.h
	code/renderergl2/tr_main.c
	code/renderergl2/tr_scene.c
	code/renderergl2/tr_world.c
	code/sdl/sdl_glimp.c