Merge branch 'force_reorganization' into 'master'

Create the forces_stress object

See merge request npneq/inq!1138

Merge branch 'parse_poscar' into 'master'

Parse the VASP POSCAR file format

See merge request npneq/inq!649

Merge branch 'do_not_calculate_forces' into 'master'

Do not calculate the forces by default

See merge request npneq/inq!401

Readme for review