Preferred workflow is to specify attribute location explicitly in the
shader. The functions remains here as some old Intel systems don't
support the required extension ARB_explicit_attrib_location (and it's
not in GL 3.0 either). Also updated and fixed the documentation.
Function bindAttribute() was renamed to bindAttributeLocation() to be
consistent with bindFragmentDataLocation().
PhongShader now uses explicit attribute location.
The class is now created always on the stack, so the user doesn't have
to delete it explicitly. It's now possible to write less verbose
shader code, instead of three lines before:
Shader* s = Shader::fromFile(Shader::Fragment, "Shader.frag");
attachShader(s);
// ...
delete s;
It's now only one:
attachShader(Shader::fromFile(Shader::Fragment, "Shader.frag"));
Removed another old overdone code, the attributes are now bound
directly, without saving the data to some temporary location and then
binding everything at once in link().