added 2-phase speed of sound, started work on cv, some problems occurred. To be continued...
Added CV functions for TTSE and normal calculations in two-phase region
Fixed bug with saturation entropy and surface tension missing in returned object from solver
Fixed bug in isobaric_expansion_coefficient, added unit conversion for thermal conductivity, included two-phase branch in code for more properties
Merge branch 'refs/heads/master' into twophaseCVandA

Conflicts:
	CoolProp/gitrevision.h
Added new functions and a linear interpolation for cp in two-phase.
hey
TTSE missing beta and kappa...
Merge pull request #24 from kaern/twophaseCVandA

Yes, looks good!
Secant obeys the maxiter parameter

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
Improvements to solvers at low pressure/temperature

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
added -_HUGE for unsupported two-phase calls with TTSE, everything works without TTSE
Moved the plotting shim functions back to CoolProp.Plots.Plots and added import to CoolProp.Plots.Plots

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
Added new switch for two-phase properties as a property in the fluid class, interpolation in state class.
Added a test file for ticket 89.
Added viscosity correlation for n-Hexane

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
Fixed bug with saturation calls using REFPROP and mixtures.  Mole fractions were not being re-calculated properly (https://github.com/ibell/coolprop/issues/28)

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
Set reference state for enthalpy for a fluid by changing phi0 terms

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>
Merge remote-tracking branch 'refs/remotes/origin/master' into twophaseCVandA

Conflicts:
	CoolProp/gitrevision.h
Added reference to Matthis' paper as Thorade-EES-2013.