Allow modification of "head_end" in piscc.ini to modify naming convention for elements and tags.
When our EEAMAS Interface was originally implemented, the HeadEnd parameter was set to "Elster", the vendor name for our meters. So all of our meters from that interface are named Elsterxxx. Elster was purchased by Honeywell, so the name no longer makes sense. We would like to change our prefix for the elements to something more generic like "MTR", since the element name is something that is exposed regularly to end users.