Unify tileconfig.json and cameraconfig.json

[jackjansen]

At the moment we use cameraconfig.json when we are obtaining pointclouds from a set of RGBD cameras, or from a set of RGBD movie files (recorded from Kinect cameras), or from a set of directories with RGB and D images (recorded from Realsense cameras).

We use tileconfig.json if we want to play back a directory full of pointclouds (and there are a few options for having a structured tree of files, to support playback of Shishir's multi-tile multi-quality streams).

It would be good to unify these (probably by merging the functionality of tileconfig.json into cameraconfig.json).

This would give us a single structure that describes where we get a stream of pointclouds from, and how to interpret them.

That could then be used as metadata in any pointcloud file format or stream format, no matter whether the streams are encoded (and possibly compressed) pointclouds, or RGB and D streams: the config metadata would have the details (and would probably contain references to the stream identifiers where the pointclouds or pointcloud tiles or RGB images or D images could be obtained from).

[jackjansen]

We should probably rename the file to cwipc_source.json or something like that.