NETSTACK_CONF_RDC_CHANNEL_CHECK_RATE for redbee-dev and econotag
Removed the obsolete MAC_CONF_CHANNEL_CHECK_RATE (now replaced with
NETSTACK_CONF_RDC_CHANNEL_CHECK_RATE)
nullrdc (previously nullrdc-framer) is now a RDC implementation that
does not do any radio duty cycling but supports link layer addresses
and frame format via framer (for example 802.15.4). nullrdc can now be
used in the same way as contikimac, xmac, etc.
nullrdc-noframer (previously nullrdc) is a null RDC implementation
that does not do any radio duty cycling, does not add any header of its
own to the packets, and does not support link layer addresses.
