centralize & clean up Syntax object construction

all built-in prim syntaxes are now kept in core.Syntaxes
instead of in the prims themselves

Syntax construction is cleaner now; but still provide SyntaxJ for for
Java laggards

extensions needed updating, of course
update extension builds to point to publicly available commit
make Scalastyle less picky about parameter count

otherwise it barfs on Syntax, as well it should I suppose
reformat Syntaxes.scala to get past Scalastyle
minor cleanup
Merge pull request #579 from NetLogo/centralize-syntax-definition

centralize & clean up Syntax object construction