remove m_random_gp
fix #1395
Try to factorize using tuple
Use variadic recursion to expand tuples

It's quite non trivial to do but it should save a lot of typing later.
Factorize spheremap too.
Factorize Unlit material
Factorize detail mat too
Fix linux compilation
Factorize transparent materials too
Use const ref in recursive variadic template unroll_arg<>::exec
Factorize all first pass materials.
Enable CPP2011 on linux.
Disable WIIUSE by default on linux.
Add asserts to catch issue early
Merge branch 'master' of https://github.com/supertuxkart/stk-code
Early exit renderSkybox without skybox textures
Wrong condition used.
Merge branch 'renderFactorisation'
Remove useless RTT and simplify rendering of icons on the minimap
Merge branch 'renderFactorisation'