This is necessary so that code in HttpServer can use framework facilities such as the thread watchdog for monitoring purposes.
Doing this shuffle meant that MainServer was moved into OpenSim/Framework/Servers
Also had to make OpenSim.Framework.Console rely on OpenSim.Framework rather than the other way around since it in turn relies on HttpServer
MainConsole and some new interfaces had to be moved into OpenSim/Framework to allow this. This can be reverted if parts of OpenSim.Framework stop relying on console presence (cheifly RegionInfo)
* If this doesn't melt the Http Server, this will significantly reduce the number of threads in use on regions with many users.
* Adds AddPollServiceHTTPHandler, and RemovePollServiceHTTPHandler to BaseHttpServer
* Generic enough to be used for many long poll services, not only the EventQueue.
