some things...
- rename "error-spec.js" to "error-detection-spec.js"
- added test cases for new functionality in getArguments(...): test if a parameter is specified more than once in a function specification (parameter with name "XYZ" already defined)
- fixed a bug in test file that caused to have to have more tests succeeded than specified. the bug was an "describe"-statement that was nested in an "it"-statement. took two hours to find the trouble maker. would be a good idea if mocha would print a warnig in such a case.