Add support for GIT Rerere

Hi,

I use a lot GIT Rerere. It's really powerful when you have to deal with lots of conflicts (this depends on your GIT usage of course).

One of the most complicated point with this tool (in my opinion) is that you have very little visibility on available recorded resolutions.

That's why I think it would be very helpful in a GIT GUI like Smartgit to be able to see a list of recorded resolutions. Or maybe to highlight the fact that a conflict was auto-solved by GIT Rerere when it is the case.

An other hard part with GIT Rerere is to deal with wrong conflict resolutions. Once you recorded a wrong conflict resolution, it is hard to know how to revert this using the forget command.

I think a GUI tool showing where Rerere did its magic and allowing to undo this magic and forget the matching resolution would be just the perfect tool to make Rerere easy to use.

I'm sure there's other great things to do about GIT Rerere in a GUI, but there's so many interesting subjects....

I hope you'll have the opportunity to add this to Smartgit one day :) 

Thanks again for your great work