Demo page is broken on HTTPS

[electricduck]

There's a reference to Bootstrap CSS over HTTP, which breaks when visiting the page at https://msurguy.github.io/ladda-bootstrap/ in Chrome/Blink-based browsers. Blink blocks mixed content completely.

[msurguy]

@electricduck updated! please check it out and close the issue if it's fixed :)

[electricduck]

Lookin' good!