Complete

• Create conflicted patch type to store conflicted patches, and associated commutation rules
• Create a new merge algorithm that handles conflicts by generating conflicted patches, temporary description of new merge can be found here:  http://codersbase.com/index.php/Darcs_Merge (doesn't always display correctly for some reason.)

In Progress

• Prove the merge algorithm gives the same answer regardless of merge order
• Create Named primitive patches

Todo

• Create cancellation patches for marking conflicted (and other types of patches) as canceled.
• Storage implementation for unresolved conflicts (store a set of conflicted parallel patches)
• unmerge, needed when something is canceled
• UI for working with conflicts