HTML5 Video Playback Speed Control Keyboard Shortcut

Add keyboard shortcuts to control HTML5 video playback rate. Available keyboard shortcuts are: <CTRL+[> = Decreate playback rate, <CTRL+]> = Increase playback rate, <CTRL+\> = Set playback rate increment/decrement unit, <CTRL+'> = Set playback to specific rate, <CTRL+;> Reset playback rate to default (to 1.0). Default playback rate incement/decrement is configurable via script.