* clutter/cogl/cogl-shader.h: Add a function for setting an
integer uniform, similar to cogl_program_uniform_1f().
* clutter/cogl/gl/cogl-program.c: Implement the GL version
of cogl_program_uniform_1i().
* clutter/cogl/gles/cogl-program.c: Implement the GLES version
of cogl_program_uniform_1i().