After pulling from Github and adding the project, make sure to add the JSON library. It is located in the /lib subfolder. To do this:

• Right click on the project and click Properties, or highlight the project and go to File -> Properties
• Go to Java Build Path and select the "Libraries" tab
• Click the Add Jars button
• Find the JSON library inside the /lib folder, and add it
• All JSON will work from this point