Try to fix crash on linux with proprietary drivers
Change xml style of screens and fix some issues with screens
Merge pull request #1371 from Flakebi/master

Change xml style of screens and fix some issues with screens
Fixed display or kart name in top left corner (caused by calling
add on the label widget twice).
Merge branch 'master' of github.com:supertuxkart/stk-code
Factorize transparent mesh rendering.
Remove code never executed.
Use a precomputed invmatrix in gi.frag

(General) matrix inversion is costly, it's better if it's done a single
time on cpu. Improve performance.
Report opengl vendor and renderer.
Merge branch 'master' into NewRTTMinimap