Fix empty comments. Remove unused code.

[alipang]

The schema file don't work with php-7.2.

[inreti-sb]

Thanks @alipang for your work! Can someone merge this and publish a new version of Quip?

[alipang]

Yes! It's good to see some action on this extra. I think I have more to come, but these are my first github and phpstorm experiences.

[rthrash]

This pull request has been mentioned on Community. There might be relevant details there:

https://community.modx.com/t/quip-not-showing-comments-properly/809/5

[rthrash]

This pull request has been mentioned on Community. There might be relevant details there:

https://community.modx.com/t/quip-reply-to-thread-showing-unapproved-for-parent-comments/838/2

[rthrash]

This pull request has been mentioned on Community. There might be relevant details there:

https://community.modx.com/t/quip-reply-to-thread-showing-unapproved-for-parent-comments/838/3

[Mark-H]

This has come up a few times now, fixing the issue each time, so would be great to get released. @JoshuaLuckers does your adoption of Articles also include Quip? :P

[JoshuaLuckers]

@Mark-H Yeah, why not! I can give it some attention now and then :).

@rthrash it would be great if I could maintain this repo (like Articles)!

[rthrash]

This pull request has been mentioned on MODX Community. There might be relevant details there:

https://community.modx.com/t/article-comment-message-coming-through-as-0/2232/5

[rthrash]

This pull request has been mentioned on MODX Community. There might be relevant details there:

https://community.modx.com/t/article-comment-message-coming-through-as-0/2232/7

[rthrash]

This pull request has been mentioned on MODX Community. There might be relevant details there:

https://community.modx.com/t/all-replay-texts-in-articles-turn-to-0/3036/3