get_vht_capa and get_vht_oper raise NotImplementedError

[coderforlife]

These functions raise a NotImplementedError meaning that if a network with those features (VHT capabilities and VHT operation) is within scanning range the nl_recvmsgs will fail, not allowing one to receive the rest of the data. It seems a better solution may be to return a dictionary (I think that is what those ieprinter functions return) that indicates it is not implemented and thus the remainder of the data still be retrieved.