Add token length to output of coap_show_pdu().
Add token length to output of coap_show_pdu().

RIOT-OS/libcoap,alexaring/libcoap,gebart/libcoap,pabigot/libcoap,authmillenon/libcoap,pabigot/libcoap,nmacs/libcoap,sgso/libcoap,fredericgermain/libcoap,joaopedrotaveira/libcoap,alexaring/libcoap,nmacs/libcoap,OlegHahm/libcoap,markushx/libcoap,thecodemaiden/libcoap-fork,fredericgermain/libcoap,joaopedrotaveira/libcoap,OlegHahm/libcoap,RIOT-OS/libcoap,alexaring/libcoap,authmillenon/libcoap,sgso/libcoap,fredericgermain/libcoap,markushx/libcoap,sgso/libcoap,pabigot/libcoap,nmacs/libcoap,OlegHahm/libcoap,gebart/libcoap,markushx/libcoap,thecodemaiden/libcoap-fork,authmillenon/libcoap,gebart/libcoap,PolymorhicCode/libcoap,joaopedrotaveira/libcoap