Simpler sed version

Created by: daviddoji

As promised, this is an attempt to simplify some of the functionality of the SED library.

There is also a notebook showing the functionality.

Known limitations

• it's supposed to be run in Maxwell, as it loads in memory the whole directory of h5 files.
• there is also a hardcoded dictionary from where to read the data from the files.

All of that can be easily changed.