added reading start

simulator_SIC_XE/src/string_reader.cpp

@@ -25,3 +25,9 @@ std::string StringReader::readString(size_t len) {
     if (static_cast<size_t>(got) < len) s.resize(static_cast<size_t>(got));
     return s;
 }
+
+std::string StringReader::readLine() {
+    std::string s;
+    if (!std::getline(in, s)) return std::string();
+    return s;
+}