started work on derivterms output
Added derivative output to Props function. Still needs som unit checking etc.
trying to validate the derivatives
Merge branch 'refs/heads/master' into derivToProps

Conflicts:
	CoolProp/gitrevision.h
Something is wrong with the second virial coefficient in the state class...
intermediate changes
Fixed derivative calculation and exposed unit conversion through CoolPropDLL. The Python wrapper now supports all kinds of unit conversions.
trying to validate the derivatives
intermediate debugging
New changes moved to master branch.

Merge branch 'refs/heads/derivToProps'

Conflicts:
	CoolProp/CoolProp.cpp
	CoolProp/gitrevision.h
	dev/Tickets/77.py