Fix mesh model resolution to use module name

This is better than using relative path since it allows mesh models to
be a dependency of the parent project.
Merge pull request #91 from strongloop/feature/fix_model_import

Fix mesh model resolution to use module name
Add pmctl support for watchdog timeout
Merge pull request #92 from strongloop/feature/watchdog_timer

Add pmctl support for watchdog timeout
Rename help text files to <cmd>.txt

The .txt extension enables customary handling for text files in my
editor, and probably other editors, like wrapping.
pmctl: add timeout argument to cpu-start