undoing preamble changes from yesterday, they cannot work

source/BandstructureParameters.en.tex

source/BandstructureParameters.tex

source/Charge.en.tex

source/Charge.tex

source/ContinuityBoundaryConditionsElectrons.en.tex

source/ContinuityBoundaryConditionsElectrons.tex

source/ContinuityBoundaryConditionsHoles.en.tex

source/ContinuityBoundaryConditionsHoles.tex

source/ContinuityEquationElectrons.en.tex

source/ContinuityEquationElectrons.tex

source/ContinuityEquationHoles.en.tex

source/ContinuityEquationHoles.tex

source/CurrentElectrons.en.tex

source/CurrentElectrons.tex

source/CurrentHoles.en.tex

source/CurrentHoles.tex

source/DensityElectrons.en.tex

source/DensityElectrons.tex

source/DensityHoles.en.tex

source/DensityHoles.tex