merge: fix unnecessary rename merges on linear update (issue631) If one side's revision is identical to the ancestor, we skip the rest of the copy detection logic.

convert: Use clone's behaviour for the default destionation name. Adjusted the documentation for this and for the fact that the destionation is created even if a name is specified.

test-symlink-basic: require symlinks availability

Add hghave utility and run-tests.py support. hghave detects system features like symlinks availability at run-time. Tests can be skipped by starting them with: "$TESTDIR/hghave" symlink || exit 80 The 80 exit status triggers hghave output handling by run-tests.py. Also, tests output can be locally patched on the fly to match reference output.

run-tests: extract correct status when script terminates with exit

Merge with -stable

diff: correctly handle combinations of whitespace options

hg grep: handle re.compile errors & update tests/test-grep

typo fix

Re: mercurial.el and hg-version-other-window hg-version-other window is unimplemented in mercurial.el. The version below works for me, YMMV.