- modularized the polling mechanisms and use function pointers instead
of macros at many places
- implemented support for FreeBSD's kqueue() polling mechanism
- fixed a warning on OpenBSD : MIN/MAX redefined
- change socket registration order at startup to accomodate kqueue.
- several makefile cleanups to support old shells
- fix build with limits.h once for all
- ev_epoll: do not rely on fd_sets anymore, use changes stacks instead.
- fdtab now holds the results of polling
- implemented support for speculative I/O processing with epoll()
- remove useless calls to shutdown(SHUT_RD), resulting in small speed boost
- auto-registering of pollers at load time