refactor list_packages_packrat -> list_packages
change state of packrat toolbar button appropriate to context
visual tweaks to packages pane (show not installed indicator, etc.)
rename list packages -> get package state
fix missing separator preceding Packrat commands in packages pane
Merge remote-tracking branch 'origin/master' into list-packages-refactor
consolide packrat context as json uses
cleaner return logic in get package state
update packages after bootstrap
Merge pull request #115 from rstudio/list-packages-refactor

Refactor package list tables and methods