removed unwanted files
Merge branch 'develop'
FIX: minor
Merge pull request #16 from Hash--/develop

This looks great.
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
CHG: moved unterminate() function into EightTerm object,
CHG: created intermediate property for T-matrices, because they
	need to be used for embedding and de-embedding.
ADD: started embed function
ADD: embed() function to Calibration2 class, implemented it for
	8-term and Oneport, and added test cases.
ADD: SOLT.embed function
ADD: SDDL Calibration object, and test-case. is not currently working
CHG: working on SDDL, changed ALMOST_ZERO to e-12
CHG: allow Network.write_touchstone() to accept absolute path
	as a filename. also changed file-opening to use the `with`
	statement, as suggested by bill thayer.

The write_touchstone functionality needs to be moved to the Touchstone
class, where it belongs.
changed Homo classes to return a consistent type . this needs
improvement
FIX: pna RF power setting  was wrongly set to an in
t
added filter_nones function to Homodict
add  real ZVA40 class, which inherits most of its commands from the
PNA . mostly works, but needs more testing
add: network to dataframe conversion function
fixed minor error
added various triggering functions