install: don't run launchctl if we don't have it

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
mercurial: don't try to re-clone histedit if we already have it

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
comm-files: use a more familiar output format

Now indicates files in both paths, just the old path, and just the new path
using a unified-diff style view, using ' ', '-', and '+' prefixes,
respectively.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>