Comment 7 for bug 904633

Here's a fix for the last caveat I mentioned. I use the "path" provided as the first argument to determine where to copy the files. It should now work for comparing across arbitrary revisions. I've also added a fallback case - in case the directory for the file being compared does not exist (has been deleted, or is in a different revision etc) it falls back to the standard schdiff.

This should work independent of where git generates the temporary files (usually /tmp, but can be changed)
All other config and gitattribute settings same as comment #3