Changing the devkitPro path from absolute to environment defined

because

* that allow placing the files in another path
Adding visual stick position to pad test

because

* it's useful for changing the stick radius
Changing ARAM test header file path

because

* it's useful for building the program
Changing the SD card reader object

in the ASM test

because

* it's useful to build the program
Changing the GU vector struct name

in the GX test

because

* it's useful to build the program