Performance:
  - Check if the compiler can optimize expression templates in such a way the expressions which occur twice are optimized
  - Make a comparision with a big code which general rule is better: Precomputer the result or do not precompute the result.
    - Check it speratly for: Unary and binary operations.
  - Check performance increase in the simple by using direct pointer for the intel compiler and on ifrit.
  - Implement reference counters for index reuse tape
  - Early out fuer passive values
  - Create an assert just for CoDiPack
  - Move static tapes out of the active real type.
  - Add support for intermixed complex and double data types.

