Calculate the exported frame base on the captured frame and the numbe…

…r of frames still waiting to be exported

Calculate the exported frame base on the captured frame and the number of frames still waiting to be exported

Improvements for feature extraction: depth

Documentation update.  NDDS last tested with UE4.22.3.

Merge pull request NVIDIA#3 from stefanbuettner/master

Fix freezing the UE editor when quitting game mode after capturing (Linux).

Add support for Linux with respective documentation update.

Add support for Linux with respective documentation update.