Use bash shell in Makefile

Necesarry to run 'cp pflua.git/{AUTHORS,COPYING,LICENSE}'.
Updated pflua
Add new pflua packet filtering application

This is an implementation of the current packet filtering application
using pflua.
Avoid loading pcap headers twice
Temporary use pflua
Adapt function filter
Add selftest for ns_responder
Add selftest for nd_light
Remove strict mode

Application crashes because Inf symbol is not defined as global symbol.
Other solution is to create symbol Inf as global in pflua.