send pending Packrat actions to client
display pending actions in packages pane
show confirmation dialog listing actions for clean, restore, etc.
Merge remote-tracking branch 'origin/master' into feature/pending-actions

Conflicts:
	src/cpp/session/modules/SessionPackrat.R
	src/cpp/session/modules/SessionPackrat.cpp
remove unused get_packrat_restore_actions
show summary of pending actions when more than one exists
track resolved and observed state, and react appropriately
Merge remote-tracking branch 'origin/master' into feature/pending-actions
improve state resolution and action display
clarify actions, enums, and simplify hash states
Merge remote-tracking branch 'origin/master' into feature/pending-actions

Conflicts:
	src/gwt/src/org/rstudio/studio/client/workbench/views/packages/Packages.java
hook up conflict state to conflict resolution dialog
share CSS for data grids used in package workflow
don't show clean actions if there are pending snapshot/restores
Merge pull request #121 from rstudio/feature/pending-actions

Display Packrat pending actions in the Action Center