Connection counter: count outgoing connections as well.

This patch lets ngIRCd count outgoing connections as well as incoming
connections (up to now only outgoing connections have been counted). This
change is required because the Conn_Close() function doesn't know whether
it closes an outgoing connection or not and therefore would decrement the
counter below zero when an outgoing connection existed -- which would
trigger an assert() call ...

Please note that this patch changes the (so far undocumented but now fixed)
behaviour of the "MaxConnections" configuration option to account the sum
of the in- and outbound connections!