Cap area

The main change is addition of the xml_post_parse.  That gets both <polygon> and <circle> though the main <circle> change will come later, if / when we can support CIRCULARSTRING or an alternative.

A few cleanup items:  cap/import.xsl needed area_desc -> name to match the schema change, and update_alert_id was using undefined variables.  I'm going by its old behavior for the fixup, so this should be checked.  However, if you want to change it *please* let me revert my change so this can be merged automatically.