* Add missing documentation;
* Fix wrong data types;
* Correctly serialize parameters without arguments.

It is not uncommon to set the `rid` as a fixed-width string with 0
padding. For Puppet, `001` is the octal number 1 and the fixed-width is
"lost", so add the ability to pass it as a string of up to three digits
like `"001"` which will be kept unchanged.

Available parameters have not changed between these versions, but doc
related to the older version will likely disapear before the one of the
latest version.