Electronic

The following needed to be addressed:

• Eigenvalue sums are now reduced over the band-group as well as the k-point group
• The Fermi level search and entropy correction are parallelised over the band-group as well as the k-point group
• The eigenvalue finder was parallelised over the band-group

Also needed to change electronic_analyse_occupancies to map the local band index to a global one, and then correctly determine the global highest occupied and lowest unoccupied states.

Completed, tested and working.