winembed and mfcembed

[Judson Valeski]

I'm getting hammered w/ "where's winembed" "how do I use winembed". but 
mfc embed is now our richest test app on windows.

perhaps we should ditch the /config dir, and make the current makefiles 
in config work for their respective test dirs?

moz/embedding/tests/winembed/makefile.win builds the test, and dumps to 
dist/winEmbed/winEmbed.exe?
same for mfcembed -> dist/mfcEmbed/mfcEmbed.exe

Jud