Allow consequents to be conjunctions of livenesses or conjunctions of safeties
Group names are now recognized with or without a trailing 's', e.g. 'office' is now equivalent to 'offices'
Add support for 'empty' groups
Add support for group-to-group correspondence
Fix bug where ordering of items in groups would not match order written in specification
Add support for 'add to group' and 'remove from group'