Options can now be selected at
command line without requiring
separate builds of the code

Also saves updated up-dir to snapshots

Plus additional goodies, such as
- equirectangular camera support
- OpenGL 3.1 support
- more accurate voxel pruning for training
- cleaner GUI

- SIMPLE_RADIAL_FISHEYE
- RADIAL_FISHEYE
- OPENCV_FISHEYE

Can also pass datasets, network configs, or snapshots as positional arguments now.

Makes f-theta and latlong modes more meaningful and paves the way for a future Orthographic mode