Fix - Single pose mode should run if "single" is specified as "type". (#514)

Author: champierre

src/PoseNet/index.js

@@ -76,9 +76,9 @@ class PoseNet extends EventEmitter {
       }
       if (this.detectionType === 'single') {
         this.singlePose();
+      } else {
+        this.multiPose();
       }
-
-      this.multiPose();
     }
     return this;
   }