Processed subhalo data and modified integrator to read and use new data structure

loadtxt.cpp

@@ -62,7 +62,7 @@ void Loadtxt::line_to_buf(std::vector<int> cols, std::string line, double *buffe
         if (col++ == cols[idx]) buffer[idx++] = std::stod(num_as_string);
     }
     if (col++ == cols[idx]) buffer[idx++] = std::stod(line);
-    if (idx < n_cols) throw;
+    if (idx < n_cols) throw std::runtime_error("Read fewer columns than expected");
 }
 
 // Below is a deomonstration. The file has multiple columns but we are only