add route and trip args to selectData, add selectTrips function

These help toward #4 so you can now get a list of trips for a given
device+date then select on them. The view is still fairly slow, even
with indexes, so may want to create rlev as a table. rlev as a view
does not get returned by getTables so the call to that function in
getColumns has been commented.
plots should take recs, not curs

replace plotDeviceDate with plotCoords, removing call to
io.selectData. The plot function should just receive a list of points
(or for now a rec array) and not a cursor to a db object. When trying
to make multiple plots with the same data, you don't want to have to
query the db each time.