Unify capitalization of OpenGL.

04/README.md

@@ -131,7 +131,7 @@ Below is an example of the HTML and JS you need to get started with shaders in t
 
 ### In **Processing**
 
-Started by [Ben Fry](http://benfry.com/) and [Casey Reas](http://reas.com/) in 2001, [Processing](https://processing.org/) is an extraordinarily simple and powerful environment in which to take your first steps in code (it was for me at least). [Andres Colubri](https://codeanticode.wordpress.com/) has made important updates to the openGL and video in Processing, making it easier than ever to use and play with GLSL shaders in this friendly environment. Processing will search for the shader named `"shader.frag"` in the `data` folder of the sketch. Be sure to copy the examples you find here into that folder and rename the file.
+Started by [Ben Fry](http://benfry.com/) and [Casey Reas](http://reas.com/) in 2001, [Processing](https://processing.org/) is an extraordinarily simple and powerful environment in which to take your first steps in code (it was for me at least). [Andres Colubri](https://codeanticode.wordpress.com/) has made important updates to the OpenGL and video in Processing, making it easier than ever to use and play with GLSL shaders in this friendly environment. Processing will search for the shader named `"shader.frag"` in the `data` folder of the sketch. Be sure to copy the examples you find here into that folder and rename the file.
 
 ```cpp
 PShader shader;