cogl-pango-display-list: Use cogl_rectangles_with_texture_coords
cogl-pango-display-list: Use cogl_rectangles_with_texture_coords

Instead of storing four vertices per rectangle in the array for a
texture node in the display list, it now only stores two in a format
that is acceptable to cogl_rectangles_with_texture_coords. That way
it can pass the array directly to that function. That function has the
advantage over cogl_rectangle that it doesn't need to validate the
pipeline for every quad so it should be slightly faster.

When the texture node is being rendered with a CoglPrimitive we now
map the buffer and expand the rectangles into 4 vertices as the data
is copied.

https://bugzilla.gnome.org/show_bug.cgi?id=656303

Reviewed-by: Robert Bragg <12e9293ec6b30c7fa8a0926af42807e929c1684f@linux.intel.com>

gcampax/cogl,gcampax/cogl,djdeath/cogl-android,djdeath/cogl,Distrotech/cogl,Distrotech/cogl,Distrotech/cogl,djdeath/cogl,djdeath/cogl-android,djdeath/cogl,Distrotech/cogl,gcampax/cogl,gcampax/cogl,collects/cogl,djdeath/cogl-android,collects/cogl