added field names to lat/long arrays

When using the Add XY Coordinates geoprocessing tool in ArcGIS, the GP tool adds two fields with the default names being Point_X and Point_Y. Having these field names in your widget by default may be useful to others when running scripts in ArcGIS and then using this widget. I forgot to add the new field names in the array manually. The GP tool I am referencing can be found in ArcMap or ArcCatalog (ArcToolBox -> Data Management Tools -> Features - Add XY Coordinates).

I know this is very minor change.....
Merge pull request #2 from friendde/patch-1

added field names to lat/long arrays