Conflict of Optados .pdos.dat file with plotting suborbitals

[NPBentley]

Currently functionality is being worked on in order to plots the dos/bands of sub orbitals (i.e. Px, Dxy or Fxxx).

It is also been suggested one should have the option to read the pdos from the optados ".pdos.dat" file.

However, there is a potential conflict here as, unlike the ".pdos_bin" castep file, the ".pdos.dat" file doesn't separate the dos up by suborbital.

[Inker2401]

The ability to read the pdos.dat has been merged in pull request #12

All optaDOS functionality is currently in optados_utils.py. We need to have a think about how this functionality can be adapted for sub-orbitals and .pdos_bin as the actual plotting will be the same, just the file read will be different.

.pdos_bin is a binary file from CASTEP we already have code in Spectral.py to read it. I think we 'just' need to make it either a module level function or more likely store the information within the Spectral' class such that it will then be available within optados_utils.py. One would then just need to set up the appropriate labels etc in DOSdata` when initialising the class and then everything else should be fine.