mq: some improvements to header rewriting (closes #690) Tested with qrefresh -m against the mm series.

Merge with crew-stable

merge with crew-stable

fix the dummy 00changelog.i not being copied on clone

Make test-convert-git compatible with other git versions (tested with 1.4.4.3)

When reverting a file which was renamed, also revert the old name

correctly record file-level history when the local side renames a directory

Fix theoretical issue in filecommit. If the file was copied, we don't want to reuse the original entry. I think this is mostly a theoretical issue - when there are copies, fp1 == nullid, so it's very unlikely that the fl.cmp(fp1, t) would think the file was unmodified. In any case, if there was a copy, we should forcefully create a new entry.

Avoid adding to the changelog executable files added by the second parent. This was a regression introduced by b51a8138292a.

avoid double slash problem mentioned in issue695