802.11: Fix default basic bit rate value for 11g (from https://github.com/aarizaq/inetmanet-2.0/commit/f2a58e8e5b95e5cb18a20b8ede27f86ae77e8a13)
Ieee80211: code optimization: Added controlFrameTxTime to compute the TX time for CTS/RTS/ACK

Included parameter controlBitrate, bit rate for Control frames.
Now basicBitrate is used for broadcast/multicast frames only

By Alfonso Ariza Quintana:
https://github.com/aarizaq/inetmanet-2.0/commit/4171344135cd0769476815f8f5472b7aac62e30b
Ieee802.11: fix for controlBitrate marameter.