Simplify/refactor things

[micha7a]

This is an issue for all things that we could do better, but we don't because it's research code ;)

• [x] simplify generating trajectory times from distances
• [x] get trajectory times from timestamps (instead of tango distances)
• [ ] use DF more in reconstructing trajectory
• [ ] get right trajectory type and model size without using specific trajectory
• [ ] make pandas float32 or numpy float64
• [ ] use DF for distance plots
• [x] clean up the mess I made in the reconstruction notebook
• [x] remove the .csv.npy files

[micha7a]

Actually it's not worth it to simplify the times from distances, because a priori we don't know how much time it will take to travel a given distance. So we would have loop anyway, just in different place. I should add comment on that in the code :/

[micha7a]

one ugly thing is that we have many .csv.npy binary files, which ideally should be csv files. It is not urgent to fix but maybe at some point we should...

I can see two options:

1. Just remove .csv from the file names
2. Use np.savetxt and add some reshaping to write and save functions