Distance Based Spatial Weights Matrix, condition on time

Creates either an inverse distance or distance-based SWM, which also excludes neighbors by date.

uses x,y coordinates to produce distance-based spatial weight matrices useful for spatial econometric regressions. Also conditions on time, so is particularly useful for hedonic regression. So, for
instance, if you are using a dataset of sales with a time horizon of a few years, you could say that homes sold over a
year before are not considered neighbors. Helps mimic the "comparable sales" approach to appraisal.
The user is asked to input x and y coordinates, as well as a lower and upper bound threshold for the neighborhood and the time window.