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

%%% should show a removed and b added
A b
R a
reverting...
%%% should show b unknown and a back to normal
? b
merging a
%%% should show foo-b
foo-b
%%% should show a removed and b added
A b
R a
reverting...
%%% should show b unknown and a marked modified (merged)
? b
%%% should show foo-b
foo-b