Fix of issue #359

- InternFormulaParser parses internTokenList directly:
  No deepcopy and better EndOfFile-Token handling.

- Implementation of the Normalization of functional and simple Brackets:
  Before internTokenList gets parsed, wrong user input brackets are
  getting corrected on the fly.Therefore will be no weird parser error
  which confuses the user.

- Implementation of Helpermethods and Exceptionhandling.

- ParserTest.testFuctionalAndSimpleBracketsCorrection() update.

- Refactoring of InternFormulaParser.