Add userid mapped parameters into FSM XML

[Richard Leys]

add a Parameters map in the core Fsm and saved in XML, to allow tools, like generators, to save parameters in the FSM.
The parameters are mapped to the userid to avoid conflicts in case of user-specific parameter values (like filesystem path etc..).

Looks like this:

<ToolsParameters>
    <Parameters userid="userid">
        <Parameter key="my.parameter">value</Parameter>
        <Parameter key="my.second.parameter">value</Parameter>
    </Parameters>

</ToolsParameters>