make Rhino not a singleton anymore

I suspect this of being a cause of intermittent TestDocking failures
on Travis and Jenkins, since we added TestEngine, which may run in
parallel with TestDocking.  but anyway, it's the right thing and
needs to happen anyway.
fix tortoise.sh to go through sbt

see 10050db5f83789029399c7373531486a25790af7 for a discussion
of the same change when it was made to shell.sh
remove unused code in compat.coffee

a little nervous about removing this since I don't remember
why it was there in the first place.  but I've been getting
"Cannot modify a property of a sealed object: toRadians" errors
sometimes, and this should make them go away.