v2.0.0 New stable version

This is a stable version: working, fast, and commented.

Now the units of measurement are those of the international system.
The timestep can be varied from 1 hour up to 1 minute.
Component models have been made more accurate.
We have added 3 new run_test.py that will guide you through the first steps of using MESSpy.

Do you want to simulate energy systems? Let's do it! And have fun!