Fixed a typo
Implemented an iterator for strings that also keeps track of the number of encountered brackets.
Added some methods to the BracketStringIterator and extended the tests to check the written methods.
InfixOperator now makes use of the new BracketStringIterator. Also added some class documentation.
FunctionOperator now used the BracketStringIterator.
Updated all operators making use of the FunctionOperator to reflect the changes made.
- fixed a bug in FunctionOperator, implemented a Test to reproduce it.
- implemented the MinimumOperator and a matching Test.
Implemented the max() operator and added it to the OperatorTestSuite
Updated the readme to contain the newly implemented functions