organized imports, trying to get source-level debugging of macro invocations right
fixed highlighting of current source line in source-level debugger when stepping through expanded macros ; line numbers in editor still broken by the fact that macro body is parsed by StartMacroNode as well
Lines of macro definition bodies are not represented by RawLineNode instances
instead of their contents just being stored in the StartMacroNode ... I
thought this might help with the line numbering issues in the
source-code editor but seems it made things even worse...