Debugging refactor

* src/pf.lua: Refactor debugging.  Use method calls to get data from the
  packet.
More pf refactoring

* src/pf.lua: Further refactoring.
Working :)

* src/pf.lua: Fix u16 access.  It works :)
tcp port 80 working

* src/pf.lua: Fix JSET compilation, and add more tests.
Slight clarity wrt optimize arg of pcap_compile

* src/pf.lua: slight refactor.