ecore_evas: Document remaining new/get calls for misc. backends

ecore_evas: Document remaining new/get calls for misc. backends

Summary:
This completes the documentation for Ecore_Evas for all (non-deprecated)
APIs.

Note that ecore_evas_software_16_ddraw_new, ecore_evas_direct3d_new,
ecore_evas_gl_glew_new, and ecore_evas_sdl16_new are left undocumented
because while they're not declared as deprecated their implementations
are either missing or marked as obsolete or legacy.  I suspect a few of
the remaining routines are likely also obsolete but I added
documentation anyway.

Reviewers: cedric

Subscribers: jpeg

Differential Revision: https://phab.enlightenment.org/D4972