Just clone that repository with:
git clone https://github.com/knitty/gui.git knitty_main
You can also download the latest version as zip file here:
https://github.com/knitty/gui/archive/master.zip
Processing requires that the folder has the same name as the main .pde file (knitty_main).
Place the files under sketchbook/knitty_main
Don't forget to download and place the libraries under sketchbook/libraries/G4P and sketchbook/libraries/sDrop g4p_controls.; // http://sourceforge.net/projects/g4p/ sojamo.drop.; // http://www.sojamo.de/libraries/drop/
This tool has been programmed by ptflea