Catch exception by reference instead of by value.

main.cpp

@@ -89,7 +89,7 @@ int main( int argc, char* argv[] ) {
     RuleBase.Load(RuleFileString);
   }
 
-  catch(TokenMatrix::BadAllocation) { // If we can't allocate memory report it.
+  catch(TokenMatrix::BadAllocation &) { // If we can't allocate memory report it.
 
     cerr << "snf2check: " << License << " ERROR_RULE_DATA!" << endl;
     return ERROR_RULE_DATA;