Opium v4.1.0

Changelog: 4.0 -> 4.1

04/10/18

1. Add designed non-local transformation to PBE0 pseudopotentials generation

2. Fix bugs for some convergence problems

Opium v4.0.0

Changelog: 3.8 -> 4.0

1. PBE0 density functional pseudopotentials can now be constructed, but only
   for non-relativistic atoms.

2. Documentation is updated, including the undocumented computational flags
   usage

3. HF pseudopotentials are available for Quantum ESPRESSO use.

Opium v3.8.0

Changelog: 3.7 -> 3.8

1. Restored the PCC version number for the recpot output.

2. Added PCC for the QE upf output.

3. Cleaned up a lot of the printing errors for the gfortran version.