ReviewViewPart skeleton implementation
RuntimeHistoryManager keeps a separate linear list of all the runtime dcs.
Get the most recent single edit operation to display the review, using the applyInverse operation.
Basic Prev/Next button implementation
Display an error message when the review command is invoked without any changes to be reviewed.
Slight change in ReviewViewPart properties.
Fixed the problem where the compare view didn't appear initially.
Move to the currently selected location
Select the involved DCs from the timeline, so that the markers would appear in the code editor area.
historyDiff -> review
Try selective undo (regional conflicts are not very well handled)
Merge branch 'feature/review_mode' into develop