[stringtemplate-interest] global boolean

[Terence Parr]

ooops. the intro of STGroup.iterateAcrossValues to make maps iterate across values ala v3 not keys like v4 could be a problem if someone uses ANTLR's Tool object in their VM *and* ST v4.  ANTLR sets this for v3 compat but if, say, eclipse calls antlr but a plugin uses ST v4 "properly"...bang!

maybe put it on STGroup instances and force antlr to set it all over in code.  i guess that is better. grr...I was stupido this weekend.

Ter