upgrade to sbt 0.13.2-RC1
Merge branch 'headless' into sbt-0.13.2
upgrade to sbt 0.13.2-RC2
Merge branch 'headless' into sbt-0.13.2
upgrade to sbt 0.13.2-RC3
Adding some tests agentset counting/stringifying in certain cases
Merge remote-tracking branch 'origin/headless' into sbt-0.13.2
upgrade to sbt 0.13.2
Merge pull request #591 from NetLogo/sbt-0.13.2

upgrade to sbt 0.13.2
make bin/shell.sh support passing model path in
wip adding syntax-only prims under core.prim
wip redo let-handling code

all tests that handle correct code are passing.
some tests on incorrect code, fail.