This is to avoid logging a 'slow' request when the source of delay is the viewer in processing a response.
This is not something we can do much about on the server end - it's server-side delay that we're interested in.
To ensure consistency, this commit also had to refactor and simplify inbound non-poll network request handling, though there should be no functional change.
IOSHttpResponse no longer exposes the Send() method, only classes in OpenSim.Framework.Servers.HttpServer should be doing this.
Only the GetTextureHandler was sending its own response. Now it leaves this to BaseHttpServer, like all other core handlers.
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.
