pp-mac: proper formatting of MAC addresses.
pp-mac: more pretty printing for dlTyp, newProto and IPs.
hex: fix bug in hex parsing

The %Lu scanf pattern does account for the leading "0x". Introduced in
92179c14.

Closes #263.

Related to #261.
Merge pull request #261 from frenetic-lang/pp-mac

pp-mac: proper formatting of MAC addresses.