Aiida-vasp

**Added**
\- A new dedicated parameter namespace `incar` override namespace that is to be used when utilizing the existing workchain stack to supply `INCAR` tags directly (needs to be valid).

- Possibility to control selective dynamics with the `positions_dof` flag.
- Added possibility to parse magnetization.
- Added framework to parse errors and warnings (notifications) from VASP.
- Nightly test runs against AiiDA core develop.
- Symbols are properly attached to `BandsData`.

**Changed**
\- Updated dependencies, in particular `parsevasp` to enable additional parsing of streams, selective dynamics and magnetization.

- Renamed override parameter namespace from `vasp` to `incar`.
- Fixed warnings related to missing context on file open etc.
- We now instead use a positive match when copying files from the restart folder so that only the required files are copying. This removes possible failures related to the restarted job failing while the parser believes the vasprun.xml etc. is okey (but in reality is from the previous run).
- Fixed missing yaml files.
- We do not allow the install of AiiDA core 1.4.0 and 1.4.1 due to a bug that caused `POTCAR` to be present in the repository.
- Removed `py` dependencies.

This is to be consider the first production release. Backwards compatibility is broken.

This is a major rewrite to be compatible with AiiDA core beta release. Backwards compatibility is broken.

**Added**
\- `vasp.base` workchain which transparently calls through to the 'vasp.vasp' calculation and restarts if appropriate.

- restarting conditions are minimal yet (only submission failed will trigger a retry)
- `vasp.relax` workchain which specializes in structure relaxation and optionally iterates until the structure converges.
- 'vasp.calc.immigrant' added in order to support VASP import Aiida-external jobs.

**Changed**
\- PotcarData.get_potcars_from_structure() now returns an entry for each `kind.name` in the structure, not one per `kind.symbol`

- PotcarData.get_potcars_dict() no longer fails if there is more than one PotcarData with the same full name in the family
- Minor changes in parser.

**Changed**
\- fixed POSCAR writing (was writing 'direct' followed by cartesian coordinates)

**Removed**
\- pruned outdated parts of documentation

**Changed**
\- missing requirement added

- PyPI description and keywords updated