Refine potree file loading

[bcasselsND]

Nick's PR does a lot of good stuff.

Make it even better:

• [x] Filter out directories we never look at -- 1_Viz, 6_Logs
• [ ] Do some operations in parallel, to speed up loading.
• [ ] file loading
• [x] (issue with rem and control point loading)
• [ ] local data #168
• [x] tracks issues Veritas#326
• [x] general clean up

[nmhaddadND]

potree #168 ties into this too. Getting an error as a result of that merge when running local data. Not sure if these issues should be together.