Bridgesim bug

Running the 50 node topology simulations for single link failures, we came across some situations where the simulator would say, cannot find link between node x and node y, while the simulator itself was showing that link in its log output on the console, right there. Investigating this message, I found that the simulator was checking for NUMBER_OF_PORTS which was #defined to be 40, whereas the port numbers were running all the way to 50. So, I went ahead and changed that in bitmap.h and rebuilt bridgesim. That solved the problem.