Adding in explicit support for "watches"

Note: this resolves #23 from the puppet-consul project
I guess I was taking inspiration from your other two defines, the Checks and Services that used this pattern.  I think I understand your suggestion and believe that is already accounted for in the bottom section, which would probably negate the need for the the explicit include.  Would you like me to make similar modifications for the other two defines that are used in a similar fashion?