FEM ConstantVacuumPermittivity/it

Description
Overwrites vacuum permitivity in Elmer electrostatic and magnetodynamic analyses with a custom value.

Usage

 * 1) To create a new ConstantVacuumPermittivity object do the following:
 * 2) * Select the menu.
 * 3) To edit an existing ConstantVacuumPermittivity object:
 * 4) * Select it in the Tree view.
 * 5) Specify a non-default vacuum permittivity value (in F/m).