aodvv2: adapted new IPC API
aodvv2: check for for debug switch correctly
aodvv2: use size_t for len parameter in writer_send_rerr
aodvv2: fixed thread entry function prototypes
aodvv2: initialize timestamp in rreq
aodvv2: eliminated debug induced warning
aodvv2: eliminated unused parameter hoplimit
aodvv2: removed unused parameter from _get_link_cost
aodvv2: eliminate warnings for unused parameters

These parameter are required for compatibility to oonf_api.
aodvv2: do not declare public aodv_get_next_hop static