cogl_clear depends on the default CoglContext which we are trying to
steer the API away from requiring. cogl_framebuffer_clear4f is
explicitly passed a framebuffer pointer which is implicitly related to a
specific context.
This updates all the examples to use cogl_framebuffer_clear4f instead of
cogl_clear and removes any redundant CoglColor that was previously
passed to cogl_clear.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
7287dd1faf
