Text data block were not considered special in the recursive purge function. So they would get deleted if they had no actual users. To fix this we instead make text data block use "fake user" so that addon authors can specify script files that should be removed if nothing is using it anymore. Per default, new text object have "fake user" set. So functionality wise, the user has to explicitly specify that they want the text object to be purge-able. Reviewed By: Bastien Differential Revision: http://developer.blender.org/D10983