Add dependencies required to function

[seangenabe]

Re: #120 #118

I was made aware that since hapi 9 some modules should now be required separately--specifically for this module, inert and vision. Can't we just add these as dependencies to the tv module? That is, making tv register inert and vision themselves instead of having the user to register them.

I don't know if that's how plugins should work now in the hapi community...

[devinivy]

It's actually a well-timed question! In the most recent release of hapi, plugins are allowed to specify that they can only be registered once then are ignored during future registrations. Once inert and vision implement this, I think your suggestion is sound. I believe inert has this change in place but not vision.

[osukaa]

I think, for now, we can only enforce the installation of inert, and vision.