Add: natcompare.js

[freddy36]

Library name

natcompare

Library license

https://github.com/sourcefrog/natsort/blob/master/natcompare.js

Library source

https://github.com/sourcefrog/natsort/tree/f8a6b0cda6de846b2a3b741967f35809de00b083

Files to include

natcompare.js