Define keyboard focus and shortcuts

[pablo]

At present, there's no clear model for managing mouse/keyboard focus in the player. This leads to such issues as:

• When keyboard tabbing through an idle HTML5 player, the hidden buttons are actually accessible and working, leading to un-anticipated player states.
• When tabbing in a playing HTML5 player, buttons are disappearing again.
• When a Flash player with visible controlbar completes, the controlbar stays visible. The logo does hide though.
• In HTML5, the controls stay visible when hovering them. In Flash the controls hide after a timeout.
• In both Flash and HTML5, the controls still hide when the mouse hovers the display.
• In Flash, the play icon highlights when hovering the controls or sidebar.

We should define and implement an easy to understand model for focus and keyboard control.

Next, we can implement a set of shortcut keys that are available to the viewer when the player is in focus:

• Space: play/pause toggle
• Left/right: seek forward and backward 10 seconds
• Up/down: raise or lower the volume by 10 percent