Improve inSensorShadow

Use point in world coordinates as arguement in order to avoid unnecessary
transformation.
Merge branch 'master' of https://github.com/AnalyticalGraphicsInc/cesium into sensorImprovements
Remove unused parameters from getIntersectionColor.:
Merge pull request #919 from fstoner/sensorImprovements

Sensor improvements
Fix Hello World in Firefox.

The Cesium container div had no styling.
Bump Cesium version to b18.
Merge remote-tracking branch 'origin/master' into explained-NaNs