Add missing curves to VRF

Also add curve limits.
Allow "Temperature" as a unit type for curves in OpenStudio.idd.
Change vrf curve type

Piping Correction Factor for Length in Heating Mode Curve changed from
CurveCubic to CurveBiquadratic.  Not used in HVAC library until now.
Merge pull request #1027 from NREL/69722310-VRFCurves

69722310 vrf curves