Add recursive makefiles.
Extend options and make help text better.

Also, get rid of `-help' and `--help', which are automatically added
by `Arg' module.  I bet there is a less hackish approach to discard
these than mine.
Run the command and act upon the return code.

FS watching is not yet implemented.  Also added some command line options.
Add `run_command command' function.

Refactor run command code form watch.