Repaired errors with Success(Msg) and CallGraph(Tree)Node, introduced in previous commits, that obstructed compilation.
Hand compiled dataflow scripts in DSL.
Renamed SimpleScriptDebuggerApp to SimpleScriptDebugger
Renamed type Script to ScriptNode
Added trait Script extends ScriptResultHolder (later maybe with others) for exposing the result variable $ etc.
Purpose: prevent clashes between features of implicit parameters "script" and "here".
Also repaired old references in GraphicalScriptDebugger to Success, which had become SuccessMsg.
Parsers.scala was by accident not included in the previous commit
Fixed chicken-and-egg problem with creating nodes for scripts in call graph and template tree.
CodeExecutors, ScriptExecutor: repaired insufficient synchronization using wait&notify; improved tracing
OperatorsSuite improved: checks for timeouts in tests; added Usage message
Cosmetic improvements to OperatorsSuite and to the synchronization between ScriptExecutor and CodeExecutor
SubScript Swing ported to JVM 8