Add linux accept4() support.
reduce the ifdef soup a little

this does leave an extra branch in.
Implement settings and sizes stats. Show information about empty slabs.
Added parameter to disable flush_all (nice to have on production)
add tests for -F option
Fix for incorrect length of initial value set via binary increment protocol.
Text protocol description grammar fix
Fix udp mode when listening on ipv6 addresses.

Previously the memcached could not respond to ipv6 udp packets correctly,
since the client's address was stored in a struct sockaddr (16 bytes on
linux) instead of a struct sockaddr_in6 (28 bytes).
Removed redundant hash computation.
explicitly record sasl auth states

It was previously possible to bypass authentication due to implicit
state management.  Now we explicitly consider ourselves
unauthenticated on any new connections and authentication attempts.

bug316

Signed-off-by: Dustin Sallings <dustin@spy.net>
Fix buffer-overrun when logging key to delete in binary protocol.
fix potential unbounded key prints

item key isn't necessarily null terminated. user submitted a patch for one,
this clears two more.
Update manpage for -F
Do not do internal item_realloc() every time

refcount == 2 is "linked and I own it"
code was doing a replace if refcount != 1 (which would mean unlinked and I own
it, in this case. If that code ever actually misfired some weird stuff might
happen).
reorder incr/decr operation to be safer.

looking for explicit refcount numbers before doing anything.

other parts of the code will require refactoring for this to be fully safe.