[Paparazzi-devel] How to return my source code to the original?

[????????]

Hi,all!

    I wanna redownload the source code from the repository again. Because I have edited the source code for some new functions but fail.And the autopilot becomes unstable after that.

    I try to redo the command: 

"$ git clone https://github.com/paparazzi/paparazzi.git"

 But it returns:

"fatal:the destination 'paparazzi' has already exit,and it is not an empty directory".

I just want to return my source code to the original.How should I do?Could I delete the code with the "drag and drop"for the paparazzi folder to the trash bin?

Thank's a lot!!