Fix message options on install command.

Added support for --use-default-message (-M) and
removed check for using -m and --do-pull together.
We will just silently ignore the messaging options
if --do-pull is not enabled.
Mention fix for #145 in the change log.
Merge branch 'master' into feature/revert
Mention new revert command in change log.
Mention PINTO_EDITOR variable in docs for the --message option.
POD formatting only.