Translations:FEM Preferences/15/en

The current supported external solvers are:
 * [[Image:FEM_SolverCalculixCxxtools.svg|32px]] CalculiX
 * [[Image:FEM_SolverElmer.svg|32px]] Elmer
 * [[Image:FEM_SolverMystran.svg|32px]] Mystran
 * [[Image:FEM_SolverZ88.svg|32px]] Z88