* Add a classfactory SocketEngineFactory to create a new socketengine of the configured type
* Implement configure hax to compile only the required socketengine and the base class
* Eliminates ugly defines, and is more in line with C++ ways
git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@4439 e03df62e-2008-0410-955e-edbf42e46eb7