Merge with crew-stable

transplant: forbid transplant to nonempty repositories with no working directory. Partially undoes d3fb413667e5.

ui.isatty() accesses sys.stdin, causing mod_wsgi to throw IOError.

hg: allow hg.parseurl(url, None) In many places hg.parseurl is called with a url and "opts.get('rev')", suggesting the second, optional argument can be None. Because opts['rev'] usually defaults to [] this never happens in practice. However, extensions don't necessarily behave the same, but do copy this pattern. Also, include wider hg.parseurl tests, beyond a demonstration of the problem.

transplant: remove the restriction that the destination be nonempty. Test fixed by Patrick Mezard <pmezard@gmail.com>

Fix subversion convert not detecting empty changesets. Need to check for the empty as list as well as None.

cvsps: fix crash when log message refers to non-existent branch (issue1615).

cvsps: add test for merge detection (issue1615). Currently only testing convert.cvsps.mergefrom; this script should also probably test convert.cvsps.mergeto.

convert/cvs: add an option to disable remote log caching Useful for debugging or testing when using --tmpdir.

tests: removed redundant "-u test" from test scripts The tests are executed with a .hgrc file which adds "-u test" by default.