Add type safe connector API and adapter to existing connector API

@martint @electrum This is the design I was talking about the other day.  It is a new API that connector writers would implement, and an adapter layer that performs parameter verification and type casts.  With this change I also remove the handle resolver and connectorId from the API as the adapter automatically handles this.  This layer could also perform the class loader isolation automatically.

I have converted the example http connector API to show what the new code will look like.

We don't need to commit this.  I wrote this as an explanation of what I was attempting to describe.  This is only took a few hours to bang out.