Rename plugin

First proposal for the rename plugin #108. It only supports cut for now and I finally settled with C because I think cleaning up the C++ interface should be handled in a different step. Please let me know if it works especially with OpenICC.
Actually, multiple renaming plugins would cause a problem, even if the meta data does not have a name clash.

Unfortunately, the contract does not support to conflict against an already provided functionality. We should add this when multiple implementations actually exist.