Uniform matrix support.

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.
diff --git a/src/mesa/shader/prog_parameter.h b/src/mesa/shader/prog_parameter.h
index fb82757..6ce96c7 100644
--- a/src/mesa/shader/prog_parameter.h
+++ b/src/mesa/shader/prog_parameter.h
@@ -77,7 +77,7 @@
 
 extern GLint
 _mesa_add_parameter(struct gl_program_parameter_list *paramList,
-                    const char *name, const GLfloat values[4], GLuint size,
+                    const char *name, const GLfloat *values, GLuint size,
                     enum register_file type);
 
 extern GLint