Generic function accepts eights (!) but optional parameter $callback, ext-network...

Generic function accepts eights (!) but optional parameter $callback, ext-network continued:
- The generic function generateOptionList() does now accept an optional eights
  parameter $callback. This is already used in ext-network to 'translate' values
  from column translation_name and can be any valid call-back function passed to
  call_user_func_array().
- Extension ext-network does now have very basic API array index translations
- TODOs.txt updated