Add dropdown for 3d-tiles example and uncomment batchID parsing

[xintongxia]

[coveralls]

Coverage decreased (-0.04%) to 29.766% when pulling 7ed6698 on xx/3d-pnts into 9067d6c on master.

[coveralls]

Coverage decreased (-0.05%) to 29.755% when pulling 0fd8180 on xx/3d-pnts into c20ba58 on master.

[ibgreen]

Lots of good progress here, approved.

I left some notes around some things that I suspect can probably be simplified, but that doesn't need to happen before landing this.

[ibgreen]

Maybe a scripts folder.

Wonder if this can be generalized and placed in root scripts.

[xintongxia]

Right now the scripts need be transpiled. I don't want to introduce all the dependencies to root, so that's why I keep the scripts in example.

[ibgreen]

Do we need such a complicated hierarchical list? Isn't it enough with just a list of the filenames?

[xintongxia]

Some examples have 2 files, one is tileset.json and the other is a binary file. Other examples have more files, I am thinking we need all the files processed in order to see the complete example.

[ibgreen]

Oh I see. The tileset.json should contain the URLs or at least filenames of all the other files (assuming they are tiles).

If that is the case, maybe we only need a list of tileset.json files...