add an ExpressionParser test

just as a nice all-in-one example of the various AST classes
point bin/issues.scala at the 5.0.6 milestone
bring issues.scala out of the dark ages

it was working before with the old version of things, but
I like to use this as example code for using Dispatch,
so it's better to be on current versions
modernize bin/issues.scala

move to Scala 2.10 and use better API for dealing with JSON

yeah, I know most of the 5.0.x branch is on 2.9, but this script is
standalone, and the latest Dispatch versions pretty much expect you to
use Future which you want 2.10 for
upgrade to Scala 2.10.4
oops need to mark a test as 2D
Merge remote-tracking branch 'origin/5.0.x'

Conflicts:
	bin/issues.scala
	headless/src/test/org/nlogo/parse/ExpressionParserTests.scala