POEx::Role::PSGIServer encapsulates the core PSGI server behaviors
into an easy to consume and extend role.  It is based on previous POEx
work such as POEx::Role::TCPServer which provides basic TCP socket
multiplexing via POE::Wheel::SocketFactory and POE::Wheel::ReadWrite,
and POEx::Role::SessionInstantiation which transforms plain Moose
objects into POE sessions.
