Constant Array 2: Enhanced declaration of array values as constants

This class can be used for declaration of array values as constants.

This class was inspired by a similarly named ("Constant Array") class written by Sourav Ray.

This class has at this point been refactored and augmented to the degree that little of the inspiring class remains beyond the concept.

This class provides the following features and enhancements as compared to Sourav Ray's original code:

- Returns booleans for non-associative array values when given (optional)
- Returns values for associative array keys when given (optional)
- Code added to validate individual keys and to retrieve values by individual keys
- Eliminates use of eval() for security and speed
- Fixes Exception handling
- Code has been reformatted

** See the class phpDoc Block for further details!