initial version of debugger stack view to do: investigate graphical feedback for frame rollover/selection; update documentation
initial version of debugger stack view
to do: investigate graphical feedback for frame rollover/selection; update documentation

svn: r9506

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket