Merge with crew-stable, fix test output

Merge with crew-stable

replace usage of os.popen() with util.popen() To make this possible, I added a mode parameter to both implementations of util.popen(), defaulting to 'r' (as it does in the Python stdlib).

test-merge-internal-tools-pattern: make executable

convert: fix svn file copy detection code

convert: fix svn branch source detection corner case It was confused by composite-looking revisions made by copy + remove.

convert: cleanup svn file copy handling

convert: handle past or foreign partial svn copies Subversion allows revisions to be composed of subparts coming from revisions before the parent or from other part of the repository. There is no simple representation for these now, keep the changes but do not track their origins.

convert: more cleanup in svn directory copy handling

convert: svn directory copy handling cleanup

convert: improve subversion branch filtering

convert: rename get_entry_from_path() into an svn_source method

convert: fix subpaths detection in svn source

test-convert-svn-branches: short identifiers are more legible

cmdutil: handle and warn about missing copy revisions

localrepo: forbid nullid copyrev

verify: check copy source revlog and nodeid

Merge with -stable

removing unused local ccache in patch.diff

merge with -stable

merge: replace readline() call, missing from posixfile_nt

Merge with crew-stable

remove trailing whitespace introduced in cfeeac24fc1e

templates/coal: spell class correctly in {fileentry}