prepended to all variables in the DBRequest list.

detector parameters from the gHcParms (THcParmList).

use the run number to determine which parameter and map files to use.

string variables from the Hall C style parameter files.  String
variables are loaded into a THaTextvars object that is held in the
THcParmList object.  PrintFull will now print all the string variables
as well as the numerical variables.  Added GetString, AddString and
RemoveString methods to access and modify the string variables.

that includes a class to read CTP style parameter files.