Free camera navigation is missing

[ComBatVision]

Basic LookAtNavigator implementation allows to change view point based on surface point and view angles of this surface point only. Camera can not view above horizon.

New feature is required to control camera independently. This feature will allow to implement UAV perspective view according to its telemetry or any other solution required free camera angles from eye point specification.

https://github.com/WorldWindEarth/worldwindjs/issues/32