Added DOI generation to the 2.0.0 upgrade process. To succeed, this script must be run on a fresh 2.0.0 database, or on a 1.9.5 version database, as those are the only ways to get the needed foreign keys to be marked as deferrable. The identifier conversion must be turned on by setting correct properties in metacat.properties. See the comments in GenerateGlobalIdentifiers for details. By default, conversion is set to false in the properties file. If you want to convert an instance to use DOIs, be sure to set metacat.properties up BEFORE running through the Metacat configuration and database upgrade.