reduce gwt permutations by eliminating all browsers but safari and gecko1_8 and using collapse-property
introduce desktop-draft mode
specify -noprecompile for faster devmode startup
add support for sourcemaps (chrome) and emulated stacks (other browsers in server mode)
check for empty source refs before attempting to resolve path
ensure focus and visibility of console prompt where appropriate during debugging
fix problems associated with language objects by moving their value lookups to R
move next button to left side of console debug context toolbar
show <unknown> for language objects that can't be evaluated
pass full stack trace for client exceptions and include method names in the log
enable raise exception diagnostic commands
basic infrastructure for server side symbol maps
hide only the non-user code on the callstack that occurs before user code
eliminate -noprecompile
finish incomplete comment
fix miscelleneous debugging issues

- Source references won't be followed if empty (JJ)
- Language objects now display correctly (Hadley)
- R/non-user code in the callstack is now visible if it is executed by user code (Hadley)
- Console now takes focus when using the debug command toolbar (JJ)

Merge remote-tracking branch 'origin/bugs/callstack'

Conflicts:
	src/gwt/src/org/rstudio/studio/client/workbench/views/console/ConsolePane.java