Sorting commit items by click on the table header in commit dialog.
In order to implement new feature I have replaced class associated with
every table row. CommitItem class encapsulate data that commit dialog
manipulates with.
Comparators are written using idiom from http://tobega.blogspot.com/2008/05/beautiful-enums.html.
Clicks on a certain column are handled in HeaderSelectionListener class.
Signed-off-by: Vasyl Vavrychuk <vvavrychuk@gmail.com>
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>