Abstracted server away into its own class, SpeechServer new inherits that

Also found where System.Web.Script.Serialization was hiding! In System.Web.Extensions!
It's more useful when converting JSON into indeterminate (read: dynamic) types.
It's also just plain easier to use; no mucking about with streams needed.
Benchmarks do show that the DataContractJsonSerializer is faster, though;
it also does verification for us. So for finalized classes, it is `probably`
better.