[BUGFIX] Raise warning if turbine_type passed without updating reference_wind_height

[misi9170]

Addresses #806 by raising a warning if FlorisInterface.reinitialize() is called with turbine_type specified and reference_wind_height unspecified.

The following code

from floris.tools import FlorisInterface

# Initialization uses NREL 5MW model with 90m hub height
fi = FlorisInterface("inputs/gch.yaml")
print(fi.floris.flow_field.reference_wind_height)

# Changing the turbine type without specifying reference_wind_height
fi.reinitialize(turbine_type=["iea_15mw"]*len(fi.layout_x))
print(fi.floris.flow_field.reference_wind_height)

# Changing the turbine type and specifying reference_wind_height
fi.reinitialize(turbine_type=["iea_15mw"]*len(fi.layout_x), reference_wind_height=150.2)
print(fi.floris.flow_field.reference_wind_height)

now raises the following warning for the line fi.reinitialize(turbine_type=["iea_15mw"]*len(fi.layout_x)):

floris.tools.floris_interface.FlorisInterface WARNING turbine_type has been changed without specifying a new reference_wind_height. reference_wind_height remains 90.00 m.

This "bug" is not specified to v4, and a similar change could be made for v3. However, since it is simply raising a warning, that may not be necessary.

[misi9170]

I just saw this method that I had not noticed before (it's called in example 18): https://github.com/NREL/floris/blob/v4/floris/tools/floris_interface.py#L94. I could update the warning to tell the user that they may want to call this method.