LANG-1050 Added new generic emptyToNull array method

Based upon the comments in [JIRA](https://issues.apache.org/jira/browse/LANG-1050), I have implemented a new generic defensive programming method for handling null arrays. The current object methods have been modified to use the method to reduce maintenance. The wrapper (and Object and Class) empty arrays have been deprecated as are no longer needed; however, are kept to maintain binary compatibility.