change resource query to VNA query
change resource query to VNA query

For consistency reasons, only use self.query instead of
self.resource.query. This function is conveniently assigned in the
__init__ function.

temmeand/scikit-rf,temmeand/scikit-rf,jhillairet/scikit-rf,jhillairet/scikit-rf,scikit-rf/scikit-rf,temmeand/scikit-rf,scikit-rf/scikit-rf,jhillairet/scikit-rf