Add an interface to ASE

Added an interface to ASE [1] on top of the Python wrapper. There is a function that will return an ASE Atoms object with the calculator already attached based on a PINY simulation. An example of use is included as well.

As this only touches my own code, I will merge the pull request if nobody complains within a reasonable time frame.

[1] https://wiki.fysik.dtu.dk/ase/