Clarify column names for coordinates in output

[jcarlis3]

This example uses the shiny app (https://west-inc.shinyapps.io/SDraw/), but I suspect it applies when using the package as well. When drawing a HIP sample of a polygon, the output CSV returned by the app includes columns named X1 and X2. These appear to be the X and Y coordinates (respectively) in the same CRS as the input polygon. It would be helpful if they were named accordingly.
Would be good to check the output of all combos (HIP for points, BAS for polygons, etc.) and ensure consistency.

Here's an example when drawing a HIP sample of a polygon of Horsetooth Reservoir (note the OBJECTID:Shape_Len columns were part of the attributes table of the Horsetooth Reservoir shapefile -- sampleID, X1, and X2 are the only columns added by SDraw):