remove debugging output
fix HeadlessModelOpener to forget plots on open()

since initForTesting() creates some
remove unused code
refactor/DRY in headless.lang
relocate tests from headless.model to headless.lang

I'm looking to merge the two packages, which overlap substantially in
functionality, and I'm starting by getting anything out of
headless.model that doesn't actually use ModelCreator
refactoring in headless.model
minor cleanup
cut dependency of TestTreeAgentSet on MockSuite
eliminate headless.model, move the tests to headless.lang

redoing them all in the headless.lang style. bye bye DSL.  (I felt
that having tests written in two styles wasn't worth the benefit,
especially so since the alternate style didn't even share the same
workspace-handling code, so it was redundant and confusing not just
for the person reading and writing tests, but also implementationally)
relocate ModelCreator to headless.lang

since we aren't using it anywhere else
beef up TestPlotModels a bit
remove unused code
fix regression in TestProfiler causing it to file under nogen

(just a silly mistake in 0d3a7dae9ae550d2667bc7d5e50e4fb207edb441)
add prim._const, ParserInterface.makeLiteralReporter

prim._const is not currently employed by the compiler, but may be
useful in some scenarios, such as for users of the controlling API.
(See TestArgumentInjection, coming soon in a separate commit, is a
sample use.)

ExpressionParser.makeLiteralReporter now supports _const and is
accessible through nvm.ParserInterface.  (Ditto on the sample use.)
make Evaluator support passing in CompilerFlags

I need this in TestArgumentInjection.  but it's just generally
a good thing.  (I'd do the same thing in nvm.Workspace, but I'm
reluctant to make life harder for people using our APIs from
Java.)
add demo code for passing arguments to job manager jobs

TestArgumentInjection is a demo written in test form.
it shows how to work around issue #413
beef up StructureParserTests with some passing tests

adding them since they're going to fail once merged to master;
it's #414
Merge remote-tracking branch 'origin/5.0.x'

Conflicts:
	src/test/org/nlogo/compiler/StructureParserTests.scala
	src/test/org/nlogo/headless/TreeAgentSetTests.scala
fix StructureParser regression (fixes #414)
Merge remote-tracking branch 'origin/master' into core