Latest view frustum work

Changes included:
* added "lens" attributes to camera class: fov, near, far, aspectRatio
* cleaned up camera class to match coding standard
* fixed ViewFrustum class to also support "lens" attributes
* notify ViewFrustum of changes in window reshape
* switch reshape() to use gluPerspective() instead of Tobias' fov&matrix operation
* use "distance" lens attributes when in View Frustum from Offset mode so you can see the entire frustum