oai2 6.x-1.3

This release rolls up all the changes that have been accumulating in the -dev branch for some time.

These include (among other things) the use of path aliases in the indentifier element and a new hook to allow other modules to add information to metadata records. It is hook_get_record_metaDataPrefix($node) where metaDataPrefix is usually "oai_dc" but could be any prefix you wish to add support for.