port portaudio/portmidi sources from pd 0.46-7. I left the full stable releases in the commits before this so that we can eventually just use those, but atm it's proving to be too complicated to use the stable pa/pm releases.

update portaudio to pa's recommended stable SVN rev 1919 (used tarball, and one of the docs wrt windows is changed from svn rev 1919, but whatever)