I think the MODULE_4_20MA (in the src folder) is only using some standard libraries:
From top src/MODULE_4_20MA.h:

#ifndef __MODULE_4_20MA_H #define __MODULE_4_20MA_H #include "Arduino.h" #include "Wire.h"

Try to download only the two files in the src-folder and see if you can include them into your project and compile.

Also: If you look at the code in src/MODULE_4_20MA.cpp you'll see that they include some register addresses, maybe that is required for this AIN4-20mA unit?