Appearance: Backport changes from Gravity back to Appearance

Make the square a rectangle with Golden Ratio
Use Set*UIColor() instead of Set*Color(ui_color())
Use B_CONTROL_BORDER_COLOR instead of hardcoding
Sort out copyright -- Haiku, Inc. didn't exist before 2003
Use variable width spacing based on font size from ControlLook
Removed unnecessary #includes

Did a little pixel pushing to make sure that everything is spaced
nicely and to ensure everything lies on integer pixel boundries.

Gravity: Use Set*UIColor() instead of Set*Color(ui_color())

Thanks jessicah!

Gravity: update copyright

This was meant to go in the last commit

Gravity: Add ColorItem and RainbowItem

instead of using boring StringItems

ColorItem draws a small colored rectangle left of the string
RainbowItem draws a rainbow colored rectangle left of the string