First part of adaptation to New installer

These two commits is preparation for agent adaptation. It adds to all agents based on SCRAgent element root that allows to get all child root on which it operates ( depending on adaptation of agent I maybe extend it with protected helper to get path of target file or FILE pointer ).
It also allow SCR server component to recognize chroot prefix that is used to initialize new scr server and when used, then set propoperly root attribute for Scripting agent that act like parent of all SCR agents. ( well confusing part is that main SCR agent is in fact ScriptingAgent, but not explicitelly told it ).