Python dependencies and comments

The script making a SFH plot for the isolated galaxy (examples/IsolatedGalaxy/IsolatedGalaxy_starformation/SFH.py) uses the tqdm package to make a progress bar. Is that necessary? I had to install this package just for that to work. Seems like a bit much for just a quick script.

@jborrow what's your view on this?

Also, the comments at the top of the files do not match what the script does.