[georss] Georss extension

[Pat Cappelaere]

For your review and EO1 imagery distribution (OWS-4 demo), I do not believe
that the georss metadata is enough for our users.  I am proposing to add a
new namespace called geonames (since Marc from geonames.org is helping...
Hope it is ok)

This adds a lot of metadata to the feed in addition to position.
Zones and regions are from Flinn-Engdahl (USGS).  This is a nice complement
over water...

Also notice the nearBy places...
This should considerably improve the search performance.

Example:

<feed xmlns:gml="http://www.opengis.net/gml"
xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"
xmlns:geonames="http://www.geonames.org" xml:lang="en-US"
xmlns:georss="http://www.georss.org/georss"
xmlns="http://purl.org/atom/ns#">

  <title>EO1 GeoBliki</title>
  <subtitle type="html">Sensor Web Enabled (SWE) Data Node </subtitle>
  <id>tag:localhost,2006:GeoBliki</id>

  ...

    <georss:where>
      <gml:Point>
        <gml:pos>-43.4858 -13.1033</gml:pos>
      </gml:Point>
    </georss:where>

    <geonames:geonames>
      <geonames:countryCode>BR</geonames:countryCode>
      <geonames:countryName>Brazil</geonames:countryName>
      <geonames:adminCode></geonames:adminCode>
      <geonames:adminName></geonames:adminName>

      <geonames:zoneNumber>729</geonames:zoneNumber>
      <geonames:zoneName>Antarctica</geonames:zoneName>
      <geonames:regionNumber>50</geonames:regionNumber>
      <geonames:regionName>Antarctica</geonames:regionName>

      <geonames:nearBy>Sítio do Mato</geonames:nearBy>
      <geonames:nearBy>Estreito</geonames:nearBy>
      <geonames:nearBy>Alagoas</geonames:nearBy>
      <geonames:nearBy>Muquém Ferrado</geonames:nearBy>
      <geonames:nearBy>Santa Rosa</geonames:nearBy>

    </geonames:geonames>
  </entry>
</feed>

Is it ok?
Marc?
Pat.