Rewrite some basic call scripts using Quaff 0.3.1.

Currently only supports TCP (until Quaff becomes NAT-aware); ISC tests have not been updated to the new Quaff version so will break.
Add missing files
Make SIPp use common Ellis code; switch registration tests over
Move PRACK and CANCEL tests, and one ISC test, to Quaff
First round of code review feedback
Add SDP to mainline call path
Fix up registrations
Add new structure to CANCEL
More code review feedback - Quaff 0.4.0 API enhancements
ISC tests cleanup
Add missing initialisation
Fix errors in ISC tests; move redirect test over
B2BUA scenario
Fix syntax error in B2BUA scenario
Fix another error in B2BUA scenario
Reflect change to TCPSource initialisation
Specify callee in B2BUA
Syntax error in B2BUA
Avoid looping in B2BUA
Fix up third-party registration