copy the stuff that is more or less useful from the crazy branch I started previously to re-factor the tool.
Removed more stuff and got the simple test label up in the preview tool window.
reorg project init, listener install
moved construction of tool window contents to the window factories
switches in editor pane now upon file save.
finally. manually registered windows. pops up now for test rule event.
parses now! got that weird IntellijIdeaRulezzz again though.
woot! displays parse tree :)
handles multiple grammars now and it remembers input and tree from multiple grammars. more comments.
factor out charstream.
add basic ast factory and start with completion to void dummy string.
add basic ast factory and start with completion to void dummy string. Lexer adaptor consume() ignores this new special char. for now it means no binary file parsing in preview.
rewinding a bit to version that works, adding the PreviewCompletionContributor.DUMMY_IDENTIFIER check in input stream.
added tooltip thing but doesn't work with punctuation :(
actually, need my tweak to reference object too.
actually, need my tweak to reference object too.
Revert "actually, need my tweak to reference object too."

This reverts commit 2347972472cafb07e9b54abefecad8dc46783869.
add useful routine, not used yet.
woot!  I finally got the input window to ignore that dummy string. The character input stream sets the end offset to the start of that dummy string. That way the lexer never sees it.  Two parsers are created, one for the auto completion process and it contains the dummy string. All we have to do is avoid setting the visual parse tree to that particular parse tree. a parse errors that come from that we don't care about.
add scrollbar to parser input console; errors now go to it instead of printing. rm junk comments.