Log and disk usage added to navbar. Settings no longer a dropdown.
Bug fixes. Efficiency improvements.

* Frames are now no longer fetch via PHP which was causing an error 500
to be thrown when dealing with very large requests. The image paths are
now generated via JS.
* Fixed a bug where the playheadTimer wasn't reinitialized after
skipping onselect() causing playback to stop working
* togglePlayPauseButton() now present to reduce some lines of code
* Old #timeline bind function for scroll zooming removed as it was
superceeded a couple of commits ago