* Improved the command line parameter handling: Allow overriding of specific parameters from a target.
For example:
$ php zs-client.php installLib --zpk=file.zpk --target=zsstaging --zsversion=6.1
The client will read the configuration parameters for the target "zsstaging" and will override the zsversion parameter with
the one provided from the command line.

* Throw an expection if wrong Zend Server version is provided.