o revised channel handling support; ifconfig now queries the kernel to
find the list of available channels and handles channel promotion;
channel attributes can be specified as part of the channel; e.g. 36:a
for channel 36 in 11a (as opposed to turbo A or HT A)
o use channel list to map between freq and IEEE channel #; this eliminates
all knowledge of how the mapping is done and fixes handling of cases
where channels overlap in the IEEE channel # space but are distinct in
the frequency+attributes space (e.g. PSB)
o add new knobs: bgscan, ff (Atheors fast frames), dturbo (Atheros
Dynamic Turbo mode), bgscanidle, bgscanintvl, scanvalid, roam:rssi11a,
roam:rssi11b, roam:rssi11g, roam:rate11a, roam:rate11b, roam:rate11g
(roaming parameters), burst, doth (forthcoming 11h support)
o print contents of WME, ATH, WPA, RSN, information elements with -v option
o print signal strength in dBm
o print noise floor in dBm
o add list txpow to print tx power caps/channel
o change default channel display in status to be more informative