[FEATURE REQUEST] Direct light

[ereator]

Is your feature request related to a problem? Please describe.
A new direct light source CLightDirect class should accompany existing spot light source CLightSpot class.

Describe the solution you'd like
Implement the CLightDirect class with the following parameters:

• Vec3f intensity
• Vec3f org
• Vec3f dir
• float hotspotRadius - radius of an inner cylinder with constant surface illumination
• float falloffRadius - radius of an outer cylinder with attenuated illumination (attenuation function might be taken from the CLightSpot class)
• bool castShadow