Compute points automatically if points is in function signature

[wenzeslaus]

Given a user function:

def run_drain(scanned_elev, points, env, **kwargs):
    my_drain(scanned_elev, points)

Function signature can be used to determine what Tangible Landscape should compute automatically and pass to the function. Points seem to be a good candidate which would greatly reduce the user code required to use points.

import inspect
parameters = inspect.signature(run_drain).parameters
if "points" in parameters:
    print("Need to compute points")

Possibly, other things can be computed automatically as well:

if "slope" in parameters:
    print("Need to compute slope")
if "classified_areas_4" in parameters:
    print("Need to classify colors into four classes")