Fix ssao blur without compute.
Use object_pass.vert for transparent objects.
Use explicit attribute location.

Should help implementing basevertex later, and simplify vao creation a
lot.
Some fixes
Simplify vao management for non instanced nodes.
Use UBO matrixes in displace.
Remove break at wrong position
Merge branch 'master' of https://github.com/supertuxkart/stk-code into ScriptEngine
Added Player Action Enums to scripts