feat: add strict mode switcher

[antongolub]

Adds compat mode for embedded IPv4 in IPv6.

import { Address } from '@webpod/ip'

Address.from('::ffff:5.6.7.8')    // ok
Address.from('1:2:3:4::5.6.7.8')  // throws

Address.strict = false
Address.from('1:2:3:4::5.6.7.8')  // now it's fine

Relates

• Additional tests for IPv6 addresses indutny/node-ip#163

[antongolub]

@richb-hanover

Fyi, your tests came in handy here. The original suite has been slightly modified, but all information about the authors, licenses, and links to the source have been preserved.

[richb-hanover]

Oh, wow! I am flattered. My one request would be to include a little more information about the provenance of the test cases, something like this:

/**
 * These test cases were borrowed and slightly adapted from richb-intermapper/IPv6-Regex.
 * All credit goes to Rich Brown, Dartware, intermapper.com.
 *
 * Provenance of the test cases: The original document at:
 * https://github.com/richb-intermapper/IPv6-Regex/blob/master/test-ipv6-regex.pl
 * collected test cases from various sources around the internet.
 *
 * THERE ARE DEFINITELY DUPLICATE TESTS. They don't matter if the test
 * function works, they take a millisecond (or less) to check.
 * 
 * Please submit updated tests cases as an Issue to this repository.
 * 
 * Original license:
 *
 * IPv6 Regex by Dartware, LLC is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License
 * To attribute this work, place a link to http://intermapper.com in the Credits or About... window of your software.
 * We would love to have you send any changes to the code or regular expression back to us at support@intermapper.com.
 */

(I also broke some long lines to be shorter. This makes it easier to read a diff, should that ever be necessary.)

Another thought: Dartware was purchased by Fortra (I was CEO until the acquisition.) I doubt that Fortra (support@intermapper.com) is interested in updating the original document (or that they even know about it.) So I added the item about updating THIS repo with any new test cases.

Thanks again!