Merge branch 'fboencapsulate'
Merge branch 'master' of https://github.com/supertuxkart/stk-code into devel
Add a fake skybox where no skybox is available

For spheremap shaders
Merge branch 'master' of https://github.com/supertuxkart/stk-code into devel
try to fix linux compilation
Revert to spheremapped reflection
Use correct mapping for spheremap
Fix texture sampled by spheremap
Spheremap: Flip y and add light.
Fix kart shadow vs kart animation (for the main player only)
Merge branch 'master' of https://github.com/supertuxkart/stk-code into devel
Try to fix linux compilations problems (apparently on some systems
Screen is defined, which then interferes with out Screen class).
Try to fix my fix for linux compilation ;)
Try to fix one more potential linux compilation problem.
first try for a Random GP generator
Merge branch 'master' of https://github.com/supertuxkart/stk-code into devel
Remove Cautics effect

It's not used anywhere and I have no way to test it so it's useless.
Factorize code drawing shadows.
Do some cleaning
Forget to remove some unused shaders.