Resource deallocation

Here is a sample test as well as the revert of the commit for the closing of the sockets.
Please note that the unit test does not end with Test so it will not be running in automatic testing, as this kind of stress test may need to run for a long period of time.

This exact same test can be used on my machine to detect resource deallocation problems in sockets as well as in polling
You are absolutely right, it does not work in every case! Currently with this implementation, user would need a call to deallocate selector in the thread that uses it. This solution proposes just this to be transparent only in the case where the context is destroyed in the same thread that uses polling. If not, as I stated in my email, they would have to call it manually. But at least they have a possibility to do it.