allow 'o' key to enter overview mode
simple support for listing S4 object slots
much more flexible sizing logic
fix compile problems on windows (sigjmp_buf); fix dangling refrence to function image
update todo
tolerate whitespace in col percent
update todo
use singular forms for slide navigation options
fix mismatched RCNTXT memory layout on Windows
basic callstack display--show callstack in a listbox when in debug mode
call frame UI: create new widget for call frame entries
add server-side support for monitoring environments at arbitrary depths
set active call frame in client when it's clicked
don't show callstack pane unless in debugging mode
use hide/show rather than create/destroy to toggle callstack pane
editor navigation menu for slides
improve splitter appearance; prepare for extracting source refs
eliminate unused imports warnings from eclipse
don't offer to expand objects with no contents
Merge branch 'feature/environment-scaffold' of github.com:rstudio/rstudio into feature/environment-scaffold