Clean Widget instantiation.

[sjohnsonaz]

Use the built in inheritance system to streamline Widget, Content, and Container.

• Move type to $prototype.
• Move Widget.create to the constructor.
• Create innerElement for Container.children.

[sjohnsonaz]

• Moved type to $prototype.
• Moved logic from init to the constructor.
• Removed directAppend, replaced with createElement method.
• Removed .panel-iterator class.

[sjohnsonaz]

All Container and Switcher actions use innerElement.