Added initial test suite

Added initial test suite. All test batches are defined under ts/tests

You can define a new test plan under ts/tests or just hacking test cases
for an existing plan in an existing .ts file

* Makefile. added new target 'test'
* pf.lua. exported filter_count()
* pf_test.lua. test suite
* ts/pcaps/ws/COPYRIGHT
* ts/pcaps/ws/telnet-cooked.pcap
* ts/pcaps/ws/tftp_wrq.pcap
* ts/tests/0001_plan.ts. test plan