initial support for arbitrary package breakpoint workflow
show correct warning bar when setting breakpoints in foreign packages not yet loaded
fix exception when clicking on a gutter with no code model
Merge remote-tracking branch 'origin/master' into feature/package-breakpoints

Conflicts:
	src/gwt/src/org/rstudio/studio/client/common/debugging/BreakpointManager.java
	src/gwt/src/org/rstudio/studio/client/workbench/views/source/editors/text/AceEditorWidget.java
deactivate package breakpoints when restarting R
fix first-assignment bug; update warning message for foreign package breakpoints
fix some comments and alignment
simplify client event generation for package load/unload
Merge pull request #42 from rstudio/feature/package-breakpoints

Support package breakpoints in packages other than the project package