Fix bug where fast scrolling fails to increase pagination limit.

Instead of debouncing, use an undocumented ngInfiniteScroll feature
named "infinite-scroll-disabled", which serves the same purpose. The
primary benefit of switching is the infinite scroll handler is fired
*after* the delay, too, which fixes this bug.

Other changes:

* Replace "Show More" button with loading indicator

* Correctly close <img> tags

* Rename reset() to resetLimit() for clarity