THIS DOES NOT CHANGE ANY EXISTING FUNCTIONALITY.
Address.pack() has been removed and all calls replaced with its synonym Address.toHeader().
Address.unpack() has been renamed to Address.fromHeader() to follow the new naming convention.
In days of yore, pack() and toHeader() used to do different things. Now they are identical and
thus one is superfluous. We have standardized on toHeader() and fromHeader().
Change-Id: Iac91c966eb6c1477f8dba0dd2ae01c84b359e539
1fa303478c