Update README.md

Author: iyotetsuya

README.md

@@ -6,7 +6,7 @@ Using [OpenCV](http://opencv.org) 2411 and [RxJava](https://github.com/ReactiveX
 * Portrait only
 * Algorithm is incorrect to draw a rectangle with four-point
 
-#Screenshot
+# Screenshot
 ![Screenshot1](https://dl.getdropbox.com/s/pvowb6np8uss82o/RD1.png)
 ![Screenshot2](https://dl.getdropbox.com/s/tjacas7nsske94y/RD2.png)