Implement _mesa_uniform_matrix()
Support for program parameters/uniforms with more than 4 elements.
Store 4x4 matrices in column-major order in registers.
Update mat mul built-in functions accordingly.
Use the gl_shader struct as it should be.
Renamed gl_linked_program to gl_shader_program.
Store both shaders and programs in the same hash table and use the Type field
to distinguish them.