AnalyticalGraphicsInc/cesium — pull request #1612 by hpinkos (2014-04-10 18:48:39+00:00)
Title: Rename Extent to Rectangle

Resolves #1553

`Extent` -> `Rectangle`
`ExtentGeometry` -> `RectangleGeometry`
`ExtentOutlineGeometry` -> `RectangleOutlineGeometry`
`ExtentPrimitive` -> `RectanglePrimitive`

I also replaced 'extent' with 'rectangle' for variable and function names throughout.