IDL API wrapper for Astrometry.net

This IDL routine uses the Python client written by the astrometrynet team (see first link below) to upload multiple fits images to the astrometry.net servers. An astrometry solution is then built, downloaded and appended to the original fits header. Please read the "README.txt" for all information. Special thanks go to exelis technical support engineers Fernando Santoro and Jim Uba for help with the spawn function at the core of the spawn_astrometrynet_api.pro procedure. Any work using this must refer to astrometry.net in the following way : "This service uses tools provided by Astrometry.net. For more details, visit http://astrometry.net/"