Try to fix #1622 (can't login due to a missing password entry field).
Merge branch 'master' of github.com:supertuxkart/stk-code
Factorise attribute binding function
Put 2d function in their own header
Remove unused functions
Move shader load code to shader.cpp instead of glwrap.hpp
Refactor library nodes to be proper TrackObjects, allows animating them with curves