Added back in attempted invocation of a step's logic function in Sequ…

…ence#checkSteps, so that an Error is thrown at startup for non-defined step logic.

lib/sequence.js

@@ -130,6 +130,11 @@ MaterializedSequence.prototype = {
           throw new Error('At step, ' + step.name + ', you are trying to access the parameters: ' + missingParams.join(', ') + ' . However, only the following parameters have been promised from prior steps thus far: ' + paramsToDate.join(', '));
 
         paramsToDate = paramsToDate.concat(step.promises);
+
+        if ('undefined' === typeof this.module[step.name]())
+          // TODO Remove this Error, since invoking the arg to typeof (see line above)
+          //      already throws an Error
+          throw new Error('No one defined the function for the following step: ' + step.name);
       }
     }
 };