Help parameter introduction like seen in JCommander

### The help parameter problem 
Many people are confused when using a help option in conjunction with required options.

See [this stackoverflow post](http://stackoverflow.com/questions/10798208/commons-cli-required-groups) for an example.

### JCommander as a problem example
JCommander is a command line parsing framework that has a solution for this: The [help option](http://jcommander.org/#Help_parameter). I like this technique very much.

### The pull request
This is a pull requrest for adding the help option including a unit test showing how to use it.