Testing trailing IPv4 parts.
Update MANIFEST
Fix the pattern part that deals with compressions and ipv4.

Also added tests for this.
Layout
Refactor.
Added the -lax option for IPv6 patterns.

This is just a short cut for -base => 'HeX', -leading_zeros => 1,
-ipv4 => 0, -single_compression => 1, -max_compression => 0. It's
equivalent to -rfc2373 => 1, with the exception that trailing IPv4
addresses will *not* be allowed.
Testing failures on incorrect separators.