New and improved examples!

[prakaa]

NEMSEER examples have been updated!

• Demand convergence examples now have two methods to calculate demand error
  • The second is a vectorised pure-pandas implementation that is much faster to execute than the pre-existing pandas + xarray version
• There is now an example that looks at energy price convergence across regions
  • This example includes vectorised code to reproduce the calculation
  • Price error is compared against demand error

Check out the new examples here