Removed DartAnalysis sln (no longer required).
Change to use snapshots instead of bleeding edge repo.
Install Json.NET :(
Switch to JSON.NET serialiser.

This will let us use the same classes in .NET for the serialization
instead of mapping them all.
Added custom deserialiser to map Google's enums to .NETish ones.
Mapped Error notifications over to JSON.NET.

Renamed classes, removed dupes that we used to map to; etc.
Mapped Highlight notifications over to JSON.NET.
Renamed classes.
Renamed class.
Mapped Navigation over to JSON.NET.
Mapped Outline over to JSON.NET.
Mapped ServerStatus over to JSON.NET.
Removed old json classes no longer required.
Fixes to match API better.