optionally hide internal functions in callstack
use positive logic for internal function view toggle
initial infrastructure work on RStudio/Shiny integration for breakpoints
use external pointers rather than environments to manage shiny function references
infrastructure for synchronous breakpoint injection during shiny app boot
Merge branch 'v0.98-shiny' into feature/shiny-debugging-improvements

Conflicts:
	src/gwt/src/org/rstudio/studio/client/workbench/views/environment/EnvironmentPane.java
	src/gwt/src/org/rstudio/studio/client/workbench/views/environment/view/EnvironmentObjectDisplay.java
	src/gwt/src/org/rstudio/studio/client/workbench/views/environment/view/EnvironmentObjectsObserver.java
pass parameters between RStudio and Shiny as an environment
first end-to-end Shiny breakpoints working (set before app boot)
improve Shiny breakpoint hit experience
improve memory management; clean up some unused code; clean up trace output
return to global environment between hitting Shiny breakpoints
narrow breakpoint scope to expression; improve encapsulation
initial infrastructure for setting Shiny breakpoints while app is running
show dimensions for large data frames
show 'unknown' for unnamed environments
Merge remote-tracking branch 'origin/v0.98-shiny' into feature/shiny-debugging-improvements
set and clear breakpoints during runtime
improve robustness for quickly setting/removing Shiny breakpoints
Merge remote-tracking branch 'origin/v0.98-shiny' into feature/shiny-debugging-improvements
fix bug: booting Shiny app with breakpoints in reactives causes double-hits