fixed bugs re: internal define-syntax
de-unitized hiding again, disabled extra navigation for now
fixed bug in letrec-syntaxes w/o var bindings
fixed bugs in block splicing
distinguished booleans and keywords in syntax browser
svn: r5578
updated to change in expansion of lexical variables
many UI updates and tweaks
improved syntax properties panel
added expand-only and expand/hide
added rudimentary textual stepper
fixed PR 8395 by adding snipclass for hrule-snip
fixed PR 8431: reductions and block splicing
fixed PR 8433: handling unquote and macro hiding w/ errors in hidden terms
svn: r5120