[commonmark]+[gfm] make autolinks compliant

[Feder1co5oave]

This fixes #1027 and replaces #638, fixes #842, fixes #813, fixes #859, fixes #593, fixes #890

It follows the commonmark spec and gfm extension spec.

• commonmark autolinks must be enclosed in < > and must be absolute URIs or email addresses.
• gfm extended autolinks are recognized without enclosing < > and can be http, https or ftp absolute URLs, URLs starting with 'www.' and email addresses.

Example 574 of the cm_autolinks test fails due to encoding problems, they'll be fixed in the next PR.

[joshbruce]

Thanks @Feder1co5oave! Seems to be failing??

#8. cm_autolinks failed at offset 1232. Near: "<p><ahref="http://example.com/\[\">http://example.com/\[\</a".


Got:
<p><ahref="http://example.com/\[\">http://example.com/\[\</a


Expected:
<p><ahref="http://example.com/%5C%5B%5C">http://example.com/

[Feder1co5oave]

Yep, I explained in my first post:

Example 574 of the cm_autolinks test fails due to encoding problems, they'll be fixed in the next PR.

I actually could have edited the test case to make it pass, but I think it's time to solve this urlencoding thing so I left it as it was in commonmark. Commonmark does url encoding.

[Feder1co5oave]

I'm thinking Travis CI integration with this repo would be really, really convenient, since you can set it up to run at every commit on master and on every pull request submitted. That way you can run tests automatically and get immediate feedback, and you could also do linting if you will.
Is there no chance that chjj could take this up and set it on the repo? After having enabled it, we could tweak the "build" process by simply committing to the source base.

[joshbruce]

Sorry, missed that. Thanks for the reiteration. Agree with the CI piece - unfortunately, I don't control that. See #967 for more details.