Prevent anchors from being hidden by header upon a new page load

Browsers change the scroll position after the page is loaded, and the current 1 ms
delay wasn't long enough for the browser to jump to the anchor. Even then, it appears
another 100ms delay is necessary to adjust the scroll properly:

http://stackoverflow.com/questions/19057731/scrolltop-on-page-reload-doesnt-work-possible-script-conflict

Add a little more of an offset to see a few lines before the anchor.

* Closes #1614
* Closes #1024

See merge request !1225