Emile: Move colorspaces to Efl.Gfx

Emile: Move colorspaces to Efl.Gfx

A small hack to the toolchain allows us to generate enums with eolian
for use by Eet and Emile (internal or otherwise non-eo libraries).

Thanks to how BUILT_SOURCES works, the eo.h files required by Emile
will be generated before they are used.

This adds a partial dependency on eo for eet and emile:
 - package dependency
 - include dependency

There is no library link dependency.