* add check

* add check

* patch

* imports

* up

* Update p3m_electrostatic_pressure.py

* format

* Update p3m_electrostatic_pressure.py

* apply patch

* exchange assert code

* docstring for test

* apply patch

* reformulate comparison

* year

* patch

* revert to np testing

* changed comparison to maximal 2 percent deviation

* changed comparison to maximal 2 percent deviation

* patch

* empty

* add tune skin

* add warmup

* patch

* refactor pressure calculation in small python class

* patch

* new style class

* add LJ to required features

* patch