Reads or writes route style properties.

If the first argument is new, a new style is created, optionally using the name provided as the second argument; else the following happens.

The first argument addresses the style and is one of:

- an integer greater than zero: style ID (styles are counted from 1)
- @current, which will pick the style currently selected
- an arbitrary style name, which will pick the first style with matching name

The second argument is one of:

- set, which will modify the addressed style using the 4th argment <arg>value</arg>
- get, where the 4th argument is omitted and the return value of the action holds the resulting value of the query
- del, which will remove the style addressed.

The 3rd argument addresses the property of the style.

Note: all operations by this action are undoable.