Xapian 'contains' method for OmegaScript

query.cc

//Added this at line 886:
CMD_contains,

//Added the function description at line 1012
T(contains,    2, 2, N, 0), //return position of substring, if not found return empty string

//Implemented contains function at line 
case CMD_contains: {
  size_t pos = args[1].find(args[0]);
  if(pos!=string::npos){
    stringstream ss;
    ss << pos;
    value = ss.str();
  } else {
    value = "";
  }
  break;
}