Fixes to IPv6 address handling
I've made some fixes to IPv6 address handling:
- make address policy assume_action work for []-quoted IPv6 addresses
- unquoted addresses are ambiguous, because of the port separator ":", and "accept" starting with 4 hex digits
- limit IPv6 mask bits to 128
- warn when comparing against an AF_UNSPEC address in a policy
- no code wants this to happen, and it produces unexpected results
Branch coming soon.