Better documentation for eina_model.
Better documentation for eina_model.

Patch by: "Jonas M. Gastal" <jgastal@profusion.mobi>



git-svn-id: a6113611d365f0fc061992be0d1d0b451b434026@67687 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

jordemort/eina,jordemort/eina,jordemort/eina