FIX: minor
Merge branch 'develop' of github.com:scikit-rf/scikit-rf into develop
DOC: added minor docstring to Coaxial object.
ADD: Network.cropped(), same as Network.crop() but returns a ntwk
CHG: moved the unterminating function inside of the EightTerm
	Calibration object.
ADD: a EightTerm.terminate() function.
	working towards an `embed` function