Improve custom player controls.

[everett1992]

• [x] Play/pause
• [x] Next
• [x] Mute
• [ ] Volume slider
• [x] Duration indicator
• [x] Current time indicator
• [ ] Accurate representation of buffered chunks
• [ ] Draggable scrubber
• [ ] FF/RW 15 seconds, or other micro adjuster.
• [x] Full width progress bar