Merge pull request #1381 from connormanning/copc

Add initial COPC and LAS 1.4 support

lasexporter should take "color" if "rgba" is not present

update 1.8 release stuff

update readme; don't await loading of root node

fox extra attribute range display

update license

update examples and readme; polishing & minor fixes

Merge pull request #492 from potree/develop

...

Merge pull request #359 from potree/develop

fix some bugs; update examples

Merge pull request #290 from potree/develop

Develop