Increasing maxFeatures to 100 to make the driver usefull. Also added
logic to try to convert gx_id to a number and using that as the id,
otherwise just use the index.


git-svn-id: https://svn.osgeo.org/gdal/trunk@26535 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_with_coverage