Tweak RunFromSourceMain so compile/run/test work
Tweak RunFromSourceMain so compile/run/test work

Tested pos/neg compilation of a simple hello world file, running said
file & a simple uTest test suite.

Uses things already downloaded in ~/.ivy2/cache, & shares ~/.sbt/boot
for the compiler-bridge component.

mdedetrich/sbt,mdedetrich/sbt,mdedetrich/sbt,sbt/sbt,mdedetrich/sbt,sbt/sbt,mdedetrich/sbt,xuwei-k/xsbt,sbt/sbt,sbt/sbt,xuwei-k/xsbt,sbt/sbt,xuwei-k/xsbt,sbt/sbt,xuwei-k/xsbt,xuwei-k/xsbt,sbt/sbt,mdedetrich/sbt,mdedetrich/sbt