test-mv-cp-st-diff: avoid linkrev collisions The copy detection code relies heavily on the linkrevs, so it's better to avoid collisions in this test.

convert: avoid querying log of foreign svn branches Server configuration may prevent access to other branches, so don't even try to get them, instead of ignoring them afterwards.

patch: check filename is /dev/null for creation or deletion (issue 1033) Otherwise, file creation or deletion is ambiguous with file being filled or emptied.

update tests for copy detection changes

copies: add tests for status -C/diff --git This goes through 42 combinations of copy/rename branch/parent/working dir.

copies: deal with symmetric difference for linear relationships choose the minimum of symmetric difference and the two revs in question

status: find copies and renames beyond the working directory

diff: use copy smarts from copies.py

copies: move findcopies code to its own module - pass in contexts - fold symmetricdifference check into copies.copies

merge: move symmetricdifferences to ancestor.py