TextureTools: fix shader compilation.

Amazingly enough this worked until now. Maybe more strict NVidia GLSL
compiler?
Reset also viewport to default framebuffer on named FB destruction.

In text example the scene was rendered with viewport used for
distance field computation, which is wrong. Also amazingly enough that
worked until now.
MeshTools: make compile() actually working with indexed meshes.

I was drunk out of my mind. Apparently didn't test once.