Add new get commands: htcaps, vhtcaps, wpa_ie
New get commands return last association parameters.
wpa_cli get htcaps; wpa_cli get vhtcaps; wpa_cli get wpa_ie
htcaps=6300000000000000000000000000000000000000000000000000
vhtcaps=000000000000000000000000 wpa_ie=30140100000fac040100000fac040100000fac0200007f0800000a0200000040460570000000003b1173737475767778797a7b7c7d7e7f808182dd07506f9a1b060180