Greater flexibility in picking bind address

Consider adding a capability to the AS along the lines of what Bela did in JGRP-1204.

An explanatory comment re JGRP-1204 from Bela:

> might be interesting for you if you want to make JGroups bind to a certain type of IP address, but don't know the exact address before startup.
>
> For example, in a cloud environment, you don't usually know the IP address assigned to you instance beforehand, unless you use elastic IPs and dyndns.org entries, for example.
>
> Since cloud provider often charge you for outgoing traffic on public IPs, you don't want replication or distribution traffic to go out over public IPs ! You rather want this type of traffic to use internal IP address, for
> which some provider (e.g. GoGrid) don't charge.
>
> This can be done by setting bind_addr or -Djgroups.bind_addr to a keyword rather than a dotted decimal or symbolic IP address:
>
> * GLOBAL: pick a public IP address. You want to avoid this for
> replication traffic
> * SITE_LOCAL: use a private IP address, e.g. 192.168.x.x. This
> avoids charges for bandwith from GoGrid, for example
> * LINK_LOCAL: use a 169.x.x.x, 254.0.0.0 address. I've never used
> this, but this would be for traffic only within 1 box
> * NON_LOOPBACK: use the first address found on an interface (which
> is up), which is not a 127.x.x.x address
>
> For my could mod-cluster demo, I set bind address to SITE_LOCAL. This works for GoGrid, need to see whether this is also true for EC2 and Rackspace

This also has implications for the AS 7 domain model.