SignalBitModel, SignalSymbolModel: deleted ser, ber.
Ieee80211OFDMDemodulator: followed recent changes.
PulseFilter, LayeredEncoder, LayeredReceiver, Ieee80211LayeredEncoder: followed recent changes.
Ieee80211OFDMModulator: the deleted TODO was not OFDM modulator related.
LayeredErrorModel: added corruptBits().
LayeredErrorModel: followed recent changes.
Ieee80211LayeredTransmitter: added missing ShortBitVector.h
Ieee80211LayeredTransmitter: rate is intended to be a member variable.