In order to satisfy the requirements for the `MessengerBase` class, the
`ISelectableItemsMessenger` class needs to take an `IHasInputs<T>`, as that is
the device that implements `IKeyName`. We may want to consider adding a
`IHasInputsMessenger` specifically for those devices that implement that
interface vs the `ISelectableItemsMessenger`.
In order to solve some dependency issues that keep cropping up, MC
should be moved back into the Essentials repo and loaded automatically
on startup. This will allow for all plugins that use the MC Messengers
library to use the same version without fear of overwriting a dll due to
loading of plugin libraries.
