rtt_stdio: update for new xtimer api
rtt_stdio: update for new xtimer api

kerneltask/RIOT,basilfx/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,avmelnikoff/RIOT,josephnoir/RIOT,syin2/RIOT,alignan/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,thomaseichinger/RIOT,toonst/RIOT,ks156/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,plushvoxel/RIOT,gautric/RIOT,roberthartung/RIOT,lazytech-org/RIOT,alignan/RIOT,kaleb-himes/RIOT,hamilton-mote/RIOT-OS,rfuentess/RIOT,neumodisch/RIOT,aeneby/RIOT,BytesGalore/RIOT,syin2/RIOT,kaleb-himes/RIOT,LudwigKnuepfer/RIOT,lazytech-org/RIOT,aeneby/RIOT,katezilla/RIOT,Ell-i/RIOT,yogo1212/RIOT,mtausig/RIOT,OTAkeys/RIOT,rfuentess/RIOT,gebart/RIOT,ks156/RIOT,hamilton-mote/RIOT-OS,ks156/RIOT,dailab/RIOT,jasonatran/RIOT,gautric/RIOT,basilfx/RIOT,BytesGalore/RIOT,miri64/RIOT,LudwigOrtmann/RIOT,jasonatran/RIOT,miri64/RIOT,gebart/RIOT,beurdouche/RIOT,mtausig/RIOT,immesys/RiSyn,OlegHahm/RIOT,biboc/RIOT,aeneby/RIOT,ant9000/RIOT,dkm/RIOT,mfrey/RIOT,kb2ma/RIOT,immesys/RiSyn,kaspar030/RIOT,OlegHahm/RIOT,LudwigKnuepfer/RIOT,rfuentess/RIOT,x3ro/RIOT,neiljay/RIOT,gebart/RIOT,smlng/RIOT,kb2ma/RIOT,kbumsik/RIOT,biboc/RIOT,x3ro/RIOT,syin2/RIOT,avmelnikoff/RIOT,cladmi/RIOT,Josar/RIOT,dkm/RIOT,TobiasFredersdorf/RIOT,Josar/RIOT,x3ro/RIOT,toonst/RIOT,aeneby/RIOT,hamilton-mote/RIOT-OS,adjih/RIOT,Josar/RIOT,TobiasFredersdorf/RIOT,toonst/RIOT,kerneltask/RIOT,x3ro/RIOT,neumodisch/RIOT,lazytech-org/RIOT,jbeyerstedt/RIOT-OTA-update,dailab/RIOT,jasonatran/RIOT,LudwigKnuepfer/RIOT,RIOT-OS/RIOT,jbeyerstedt/RIOT-OTA-update,LudwigOrtmann/RIOT,neiljay/RIOT,roberthartung/RIOT,x3ro/RIOT,TobiasFredersdorf/RIOT,kb2ma/RIOT,mtausig/RIOT,jfischer-phytec-iot/RIOT,thomaseichinger/RIOT,BytesGalore/RIOT,neiljay/RIOT,adjih/RIOT,authmillenon/RIOT,thomaseichinger/RIOT,RIOT-OS/RIOT,jfischer-phytec-iot/RIOT,LudwigOrtmann/RIOT,cladmi/RIOT,gautric/RIOT,miri64/RIOT,dkm/RIOT,Ell-i/RIOT,kaspar030/RIOT,kaspar030/RIOT,miri64/RIOT,katezilla/RIOT,OlegHahm/RIOT,kaleb-himes/RIOT,jfischer-phytec-iot/RIOT,Hyungsin/RIOT-OS,LudwigKnuepfer/RIOT,lazytech-org/RIOT,adjih/RIOT,kerneltask/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,josephnoir/RIOT,A-Paul/RIOT,dailab/RIOT,miri64/RIOT,mfrey/RIOT,cladmi/RIOT,smlng/RIOT,BytesGalore/RIOT,LudwigOrtmann/RIOT,basilfx/RIOT,kYc0o/RIOT,cladmi/RIOT,neumodisch/RIOT,biboc/RIOT,beurdouche/RIOT,biboc/RIOT,Josar/RIOT,ant9000/RIOT,LudwigKnuepfer/RIOT,roberthartung/RIOT,authmillenon/RIOT,kaleb-himes/RIOT,Hyungsin/RIOT-OS,mfrey/RIOT,kb2ma/RIOT,adjih/RIOT,backenklee/RIOT,alignan/RIOT,jfischer-phytec-iot/RIOT,kerneltask/RIOT,Hyungsin/RIOT-OS,dkm/RIOT,immesys/RiSyn,syin2/RIOT,jfischer-phytec-iot/RIOT,kb2ma/RIOT,mfrey/RIOT,adrianghc/RIOT,kYc0o/RIOT,aeneby/RIOT,backenklee/RIOT,toonst/RIOT,kaspar030/RIOT,TobiasFredersdorf/RIOT,basilfx/RIOT,hamilton-mote/RIOT-OS,kbumsik/RIOT,rfuentess/RIOT,authmillenon/RIOT,A-Paul/RIOT,neumodisch/RIOT,katezilla/RIOT,syin2/RIOT,katezilla/RIOT,roberthartung/RIOT,kbumsik/RIOT,plushvoxel/RIOT,smlng/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,avmelnikoff/RIOT,roberthartung/RIOT,Ell-i/RIOT,OlegHahm/RIOT,A-Paul/RIOT,immesys/RiSyn,adrianghc/RIOT,mfrey/RIOT,adrianghc/RIOT,thomaseichinger/RIOT,avmelnikoff/RIOT,backenklee/RIOT,neumodisch/RIOT,neiljay/RIOT,OTAkeys/RIOT,adjih/RIOT,yogo1212/RIOT,plushvoxel/RIOT,Ell-i/RIOT,dailab/RIOT,ant9000/RIOT,josephnoir/RIOT,jasonatran/RIOT,gebart/RIOT,jbeyerstedt/RIOT-OTA-update,yogo1212/RIOT,backenklee/RIOT,plushvoxel/RIOT,authmillenon/RIOT,josephnoir/RIOT,A-Paul/RIOT,OTAkeys/RIOT,A-Paul/RIOT,cladmi/RIOT,Hyungsin/RIOT-OS,RIOT-OS/RIOT,beurdouche/RIOT,biboc/RIOT,smlng/RIOT,backenklee/RIOT,alignan/RIOT,avmelnikoff/RIOT,BytesGalore/RIOT,yogo1212/RIOT,TobiasFredersdorf/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,ks156/RIOT,kaleb-himes/RIOT,ant9000/RIOT,immesys/RiSyn,rfuentess/RIOT,thomaseichinger/RIOT,mtausig/RIOT,dkm/RIOT,LudwigOrtmann/RIOT,authmillenon/RIOT,toonst/RIOT,beurdouche/RIOT,adrianghc/RIOT,gautric/RIOT,neiljay/RIOT,basilfx/RIOT,hamilton-mote/RIOT-OS,OTAkeys/RIOT,gautric/RIOT,beurdouche/RIOT,immesys/RiSyn,yogo1212/RIOT,OlegHahm/RIOT,kYc0o/RIOT,katezilla/RIOT,authmillenon/RIOT,kYc0o/RIOT,jbeyerstedt/RIOT-OTA-update,kaspar030/RIOT,OTAkeys/RIOT,Josar/RIOT,Ell-i/RIOT,Hyungsin/RIOT-OS,ks156/RIOT,josephnoir/RIOT,gebart/RIOT,adrianghc/RIOT,kbumsik/RIOT,kbumsik/RIOT,ant9000/RIOT,alignan/RIOT,plushvoxel/RIOT,smlng/RIOT,jbeyerstedt/RIOT-OTA-update,yogo1212/RIOT,kYc0o/RIOT,jasonatran/RIOT,mtausig/RIOT,lazytech-org/RIOT,neumodisch/RIOT,kerneltask/RIOT,dailab/RIOT,LudwigOrtmann/RIOT