Fix bug where fast scrolling fails to increase pagination limit.

Instead of debouncing, use an 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