Evas: Don't pass whole RGBA_Image to low-level render functions

Evas: Don't pass whole RGBA_Image to low-level render functions

Idea originated from Cedric the b0rker.

This is a big fat search-and-replace commit.
This commit also introduces space changes... Sorry for the mix.

NOTE: This commit may have one side effect as there was some very
      dubious code chaning the dst image's alpha flag in the
      Gfx get functions. Logically this didn't make sense (at
      draw time the dst alpha should already be well defined),
      so it should be safe.