merge with mpm

merge with stable

context: fallback function should not return None

test-subrepo-svn: fix strange svn behaviour on windows I got a full path when pusing the external like: Sending C:/foo/bar/test-subrepo-svn/sub/t/s/alpha instead of the relative path

tests: force color ansi mode on Windows

acl: improve undefined group error handling

test-acl: avoid $HGTMP on windows sed does not like colons and there are other path normalization issues.