timeout code can now be enabled via autoconf with --enable-idle-timeouts

Conflicts:
	memcached.c
	memcached.h
added some edge-case code to attempt to make sure timeouts are in lock-step with the state machine
interspersing macros and string constants not supported by older versions of gcc

Conflicts:
	memcached.c
add stats tracking for idle disconnects

Conflicts:
	memcached.c
	memcached.h
moved timeout code to its own function
added verbose output

Conflicts:
	memcached.c
don't remove expired event timers which aren't using EV_PERSIST