Add method read_core_state_eigen to class Outcar in order to read core state
eigenenergies.
See VASP keywords CL*
Add an OUTCAR file with a core state calculation
Add test for Outcar.read_core_state_eigen() method
Merge branch 'master' of https://github.com/materialsproject/pymatgen into corelevel
Merge pull request #1 from gVallverdu/corelevel

Corelevel
Merge branch 'master' of https://github.com/gVallverdu/pymatgen into surface