Implement a central command line controller
Currently FLOW3 provides a command line interface through the flow3.sh bash script which has a fixed support for certain commands. This logic of this script should be extracted and improved so that we'll end up with very lean flow3.sh and flow3.bat scripts which just pass the command line arguments to a FLOW3CLI.php script.
The FLOW3CLI should allow for simple registration of additional commands so that third party packages can also take advantage of the interface. In the long run this script could also provide an interactive shell which allows for executing the available commands.