"Event" Themes

Given a table of data, which includes two columns, "x" and "y" or "lat" and "lon" or "easting" and "northing", a process (Table -> Create Event Theme) can be run to create a new layer/file/spatialtable with points reflecting those coordinates. The UI should be fairly "smart" in checking the attribute names for "well known" column names and using them by default as the inputs (if there are "lat" and "lon" columns in the table, then those are what should be used). It should also be smart enough to deal with the bane of event table processing: lat/lon coordinates expressed in degrees/minutes/seconds – there are a large number of variations on this "format", so the regex will have to be fairly careful and complete.