Various fixes

Sorry that it is just two big commits...

Changes released under the MIT license.
You're right, it shouldn't be. I commented it out because it was spamming me before I added METAFILE_RECORD_DIBSTRETCHBLT (all the data of a bitmap!) and I couldn't see the "Unimplemented" message.

I just changed to g_warning because I'm not a C programmer and was debugging from within a Mono application. It was one way to get it to actually show me the messages. I saw it being used in gdip_metafile_play_setup, saw that it showed up for me when the printf's didn't, so replaced printf's in wmfcodec.c and metafile.c with that.