Added the str() function to evaluate the given value (string or PrimitiveString) and return the native string value.
Added a compare() function.
Based the areEqual() function to the new compare() function and make use of the str() function to validate arguments.
Consolidated all functions to use the str() function to allow for string as well as PrimitiveString arguments indistinctly.
Added the concat() function.
Fixed an issue with the concat() function when concatenating arrays.
Added the concat() function tests.