Add command for doing a name resolution on client.

Resolve command now can resolve given hostname(s) on director, client
and storage daemon if specified.

examples:

* resolution on director:
   resolve www.bareos.com
   > gonzo-dir resolves www.bareos.com to host[ipv4:84.44.166.242]

* resolution on client:
   resolve client=gonzo.bareos.com-fd www.bareos.com
   > gonzo-fd resolves www.bareos.com to host[ipv4:84.44.166.242]

* resolution on storage:
   resolve storage=File www.bareos.com
   > gonzo-sd  resolves www.bareos.com to host[ipv4:84.44.166.242]

Fixes #181: Add command for doing a name resolution on client.

Signed-off-by: Marco van Wieringen <marco.van.wieringen@bareos.com>
Use ; to seperate fields in address instead of :.

Now that IPV6 is more and more common use a semicolon instead
of a colon as seperator for the different fields of an address.