tests/driver_at: adapt test app to new API
tests/driver_at: adapt test app to new API

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