Try to replace Sauce Labs, so CI works for pull requests (#774).

Based on configuration at 60c73499fc/README.md.

* Add scale option to hot spot

When `true`, the hot spot is scaled to match the fish eye effect of the image.

Hot spots then appear to be embedded in the panorama instead of floating on top.

This regression was introduced in 12516e69b9.

* Add optional pitch argument to startAutoRotate

Before starting rotation, the viewer is panned to `pitch`.

If pitch is not specified, origPitch will be used

This resolves pixelation issues on some mobile devices (fixes #725).
It also may be related to issues #301, #496, #683, and #708.

For three event listeners added to the container elements weren't being
removed properly, since `removeEventListener` was mistakenly being called on
`uiContainer` instead. This was preventing garbage collection.