Added support to specify hostnames in the bind directive in redis.conf

Hi, 

Specifying a host name as opposed to an IP address in redis.conf, throws an invalid bind address error. This patch provides a simple mechanism (using tools already found in anet.c) to allow host names. 

It would be probably better to use getaddrinfo, since gethostbyname is deprecated, but that would mean to rewrite a big part of anet.c.

Cheers,