Revert "Example Graphene Wannier orb files"

This reverts commit 773dd97a9810211349df2a9c0ccf493969dc7df3.
improve performance in local_density
changing ldos example file
changing ham matrices to complex
changing plotter functions
removing imports
adding vector potential, magnetic field and calculation of band
structure
Merge branch 'master' of https://github.com/zonksoft/envTB into wannierfft
Merge branch 'wannierfft' of https://github.com/zonksoft/envTB into wannierfft