[swfmill] mp3 import fix

[Robin Palotai]

Hello All!

After some investigation, I found that swfmill's mp3 import code was a
bit limited, allowing only to import 44.1kHz stereo mp3 (a bit better
in subversion, but still not complete).

With this fix, all the flash-supported 44, 22 and 11kHz mono/stereo
mp3's can be included.

Apply the patch to or simply overwrite src/swft/swft_import_mp3.cpp of
swfmill (either targz or svn).
http://www.mindless-labs.com/blog/files/swfmill-0.2.12-mp3.patch
http://www.mindless-labs.com/blog/files/swft_import_mp3.cpp

Maybe this can make it to the repository if provides to be correct.

Good luck swfmilling!
Robin