[CREATE] OpenRaster proposal: save currently selected layer

[Andrew Chadwick]

Some running code, for the furthering of rough consensus:
https://gitorious.org/~achadwick/mypaint/achadwick-mypaint/commit/0f06c5b .
I'll push it to master when all's agreed.

Merge request for the standard's schema files:
https://gitorious.org/openraster/openraster-standard/merge_requests/1 -
could someone review and merge please?

Both cover edit-locked as well, but I don't want to spam two threads
with the same info.

-- 
Andrew Chadwick