If one is not passed, they will default to an EmptyServiceProvider

This resolves issues where since the merging of OnModuleBuilding, users
were effectively forced to use the DI pattern, where before they were
not.

While this isn't necessarily a bad idea, we shouldn't just change this
behavior for no reason (though I assume making the IServiceProvider
argument required was a mistake)

* C#7 features in commands, CommandInfo in ModuleBase

* Update TypeReaders with C#7 features and IServiceProvider

* Add best-choice command selection to CommandService

* Normalize type reader scores correctly

* Fix logic error and rebase onto dev

* Change GetMethod for SetMethod in ReflectionUtils

Should be checking against setters, not getters

* Ensure args/params scores do not overwhelm Priority

* Remove possibility of NaNs

Not pretty, but it works.