I just published a prerelease of my work on the PlayMusicExporter on GitHub, feel free to grab the apk here.
My changes:
I completely rewrote the settings UI, because the old one was using deprecated classes and methods, and some of the settings weren't working anyway. The settings now use the newer PreferenceFragments instead of the old PreferenceActivity and they (as far as I know) all work (EDIT: Some still don't work).
The other change is that I integrated my old fork, which is for automated exports of all downloaded/cached songs, which is now accessible via a submenu in the settings.