I represent a perspective projection.

Instance variables:
nearDistance <Float> Near clipping plane distance
farDistance <Float> Far clipping plane distance
fieldOfView <Float> The field of view covered by the perspective
aspectRatio <Float> The aspect ratio to be included

	converting
	asFrustum asMatrix4x4

	accessing	top
	aspectRatio
	aspectRatio:
	farDistance
	farDistance:
	fieldOfView
	fieldOfView:
	nearDistance
	nearDistance:

	converting	top
	asFrustum
	asMatrix4x4