Merge pull request #487 from tdwg/buildxml

Darwin Core extension XML file building script.

Merge pull request #381 from tdwg/extbuilder

Amendments following review of resulting XML files by GBIF.

Solutions to issues 313, 307, and 243.

Darwin Core standard release 2014-11-08.

Darwin Core standard release 2013-10-23.

Darwin Core standard release 2011-10-26.

Darwin Core standard release 2009-12-07.

First Darwin Core standard release 2009-10-08.

Pre-standard release 2009-09-23.

Pre-standard release 2009-07-06.