[BUG] Fix for issue #153. makewindows -s should not be required with -b.

src/windowMaker/windowMakerMain.cpp

@@ -135,7 +135,7 @@ int windowmaker_main(int argc, char* argv[]) {
         cerr << endl << "*****" << endl << "*****ERROR: Can't combine -w (window size) and -n (number of windows). Please use one or the other. " << endl << "*****" << endl;
         showHelp = true;
     }
-    if (step <= 0) {
+    if (step <= 0 && !haveBed && haveGenome) {
         cerr << endl << "*****" << endl << "*****ERROR: The step (-s) option must be greater than zero. " << endl << "*****" << endl;
         showHelp = true;
     }