Remove system properties

[HugoMario]

Now that custom arguments have been implemented we can remove the system properties and use custom arguments instead.

[jmini]

Have a look at commit dac94a7 for an example.

I track this change as new section in my migration how-to: replace-system-properties-with-custom-arguments (feel free to improve it)

[HugoMario]

i will, thanks @jmini