update README.md with tiny-dnn

tiny-dnn in its recent version updated the testing framework to GTest.
We would like to be mentioned as consumers of the project.

README.md

@@ -60,6 +60,7 @@ the following notable projects:
   * [Protocol Buffers](https://github.com/google/protobuf), Google's data
     interchange format.
   * The [OpenCV](http://opencv.org/) computer vision library.
+  * [tiny-dnn](https://github.com/tiny-dnn/tiny-dnn): header only, dependency-free deep learning framework in C++11
 
 ## Related Open Source Projects ##