Removed the "X-" prefix from our custom HTTP headers since X- has been deprecated in [RFC 6648](http://tools.ietf.org/html/rfc6648)
Renamed legacy "PluginResultsStore" to "TabResultStore"
Turned on documentation xml files in Glimpse.Core.csproj
Switched Constants.cs to internal
Documented the *.ClientScript namespace, and associated types. Sealed several types.