hgmerge: various cleanups Details: - put temporary file names into variables - make all temporary file names end with random part - cleanup FileMerge handling - do not use hardlinks in FileMerge change test (breaks on FAT) - try harder to keep file mtime unchanged in case of failed merge

removing b
this update spans a branch affecting the following files:
 b
aborting update spanning branches!
(use update -m to merge across branches or -C to lose changes)