Merge pull request #251 in VECTO/vecto-sim from...

Merge pull request #251 in VECTO/vecto-sim from ~EMQUARIMA/vecto-sim:feature/VECTO-333-remove-folder-with-declaration to develop

* commit 'd93ea5e9':
  more refactoring
  refactoring: variable names match coding style, more cleanup (engine)
  Refactoring: renaming classes to fit naming conventions
  removing commented lines (during refactoring/removing vecto 2.2 core), removing redundant qualifiers
  more cleanup: remove batch tab, remove developer options, remove shutdown, remove cmdline args
  removing declaration folder
  adapting vecto gui to get rid of 'Declaration' Folder and use declaration data from vecto core; refactoring, removing no longer required files / classes
  refactoring reading retarder type, adding missing file, physics constants also in declaration class
  allow lookup of (currently) disabled vehicle classes (for GUI)
  provide method to convert velocity to km/h
  extending auxiliaries classes to provide list of available auxiliaries (for GUI)
  extending helper classes for enums (to be useful for GUI)