Adding in explicit support for "watches"

Note: this resolves #23 from the puppet-consul project
That is certainly an option.  Again, I had tried to "remain true" to the behavior exhibited in the other two defines, which had explicit checking for the "required" attributes.  In truth, only "type" is absolutely required by Consul to properly parse the Watch and act upon it.  

I do not have a problem removing the explicit "fail fast" upon the logical error of not declaring the handler attribute, however the Type is a required attribute of a watch.