More sims per channel

[marcobortolami]

This PR generalizes the scripts e2e_simulation.py and run_simulation.py in order to run multiple simulations for the same channel without recalculating quaternions, pointings, etc.

[marcobortolami]

I should have completed the generalization. I tested that the files are produced in the correct folder, even when running sim0000, both running with 1 or 2 sims at the same time.
Few comments:

1. I ran with just 2 detectors for 1 year to debug, just checking that the files are there, but I haven't run for a real case yet, nor tested that the outputs are correct (I mean, validating them).
2. I wonder if we can improve line 122 of the e2e script, i.e. this. I don't like the way I implemented the base_path change (just taking the characters up to the 33rd from the end), but this works and nothing better came to my mind. Any more elegant ideas? Or do we leave this like it is implemented now?
3. I have not tested madam, only the binned maps by lbs. However, I generalized the code related to madam.

So, I leave here a to-do list:

• generalize code
• perform serious validation
• think about base_path update
• test madam

[marcobortolami]

I corrected a small bug on the memory freeing of the tods when passing from sim000x to sim000y with x,y not 0.