tools/compile_test_one_board: update documentation README
tools/compile_test_one_board: update documentation README

Provide some notes on how to perform basic checks on the script using tox

kaspar030/RIOT,josephnoir/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,toonst/RIOT,basilfx/RIOT,mfrey/RIOT,OlegHahm/RIOT,lazytech-org/RIOT,mtausig/RIOT,basilfx/RIOT,ant9000/RIOT,miri64/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,rfuentess/RIOT,mfrey/RIOT,toonst/RIOT,OlegHahm/RIOT,smlng/RIOT,x3ro/RIOT,jasonatran/RIOT,x3ro/RIOT,OTAkeys/RIOT,basilfx/RIOT,lazytech-org/RIOT,mtausig/RIOT,miri64/RIOT,rfuentess/RIOT,mfrey/RIOT,cladmi/RIOT,ant9000/RIOT,kYc0o/RIOT,josephnoir/RIOT,rfuentess/RIOT,basilfx/RIOT,josephnoir/RIOT,miri64/RIOT,aeneby/RIOT,OlegHahm/RIOT,BytesGalore/RIOT,authmillenon/RIOT,aeneby/RIOT,lazytech-org/RIOT,lazytech-org/RIOT,basilfx/RIOT,cladmi/RIOT,mtausig/RIOT,smlng/RIOT,mfrey/RIOT,A-Paul/RIOT,authmillenon/RIOT,yogo1212/RIOT,miri64/RIOT,cladmi/RIOT,yogo1212/RIOT,kaspar030/RIOT,A-Paul/RIOT,BytesGalore/RIOT,toonst/RIOT,RIOT-OS/RIOT,toonst/RIOT,kaspar030/RIOT,jasonatran/RIOT,BytesGalore/RIOT,josephnoir/RIOT,kYc0o/RIOT,jasonatran/RIOT,yogo1212/RIOT,authmillenon/RIOT,ant9000/RIOT,toonst/RIOT,mtausig/RIOT,jasonatran/RIOT,rfuentess/RIOT,yogo1212/RIOT,yogo1212/RIOT,aeneby/RIOT,kaspar030/RIOT,aeneby/RIOT,A-Paul/RIOT,jasonatran/RIOT,authmillenon/RIOT,authmillenon/RIOT,x3ro/RIOT,smlng/RIOT,yogo1212/RIOT,miri64/RIOT,x3ro/RIOT,BytesGalore/RIOT,kYc0o/RIOT,ant9000/RIOT,cladmi/RIOT,authmillenon/RIOT,kYc0o/RIOT,A-Paul/RIOT,BytesGalore/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,A-Paul/RIOT,smlng/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,ant9000/RIOT,rfuentess/RIOT,mtausig/RIOT,cladmi/RIOT,OlegHahm/RIOT,lazytech-org/RIOT,smlng/RIOT,mfrey/RIOT,kaspar030/RIOT,x3ro/RIOT,aeneby/RIOT