Version install of dependencies

[TylerLeonhardt]

I was looking at these lines and realized that the current code will not fetch a newer version of MacNotify/PSNotifySend if one exists.

We should change this to:

(Get-Module -ListAvailable MacNotify).Version -gt x.x.x

where x.x.x is the minimum version required to use this module.

Today, we're ok, but for -SoundFile we'll have to take this into account because I added it in later to PSNotifySend

[TylerLeonhardt]

We'll need this issue fixed for #9