Various experiments related to StringBuilder.

Conclusions:

1) The <use-library> certainly does NOT cause the libraries to be added to the APK. Busted!

2) It's amazing how much of the (admittedly simple) App will run without any scala run timelibrary support

3) The build is sooo much quicker without proguard that I need to continue this path somehow for development convenience. Rooting here I come?