Callback paramLine can now have a domain instead of an ip address.

Change-Id: I4e0c7cd9aea38cd9ca7d5f9c3335f94ab48bcb14
Refactored CallbackHelper.java to parse the callback's address and port in a more straightforward way.

Change-Id: I4b614867b42a9474ce48b0026a7115b9f4a7266b
Merge branch 'CLB-594-CALLBACK-HELPER-DOMAIN' into 1.23-candidate