depth clamping

[bmegli]

Currently when distance exceeds maximum representable distance, it is clamped at maximum value.

With advanced controls->depth table->depth clamp max it is possible to get other behaviour (looks like 0 when exceeding depth clamp max)

To decide which behavior is better.

Now it's:

• missing data is 0
• data over max distance is max_distance

When translating to point cloud both special values would have to be taken into account.

[bmegli]

Chosen solution to:

• clamp above P010LE encodable range
• return those values as 0

Done directly on Realsense using advanced options:

• DepthTable.DepthClampMax

[bmegli]

Added behaviour explanation on wiki how-it-works