Use 'nt:resource' instead of 'mode:resource' when used with 'nt:file'

Originally, JCR 1.0 defined 'nt:resource' to be 'mix:referenceable', so ModeShape defined 'mode:resource' to be equivalent but without the 'mix:referenceable' behavior. JCR 2.0 changed the 'nt:resource' node type to no longer extend 'mix:referenceable', making 'mode:resource' obsolete. Therefore, we can remove uses of it, primarily from the file system connector, the SVN connector, the ZIP file sequencer. However, it is still used within the configuration system (though not quite in the same way that a 'nt:resource' is used).

Any persisted information should remain valid, however. This shouldn't be a problem for the file system and SVN connectors, since they recreate the primary type information from the files (or recover persisted information from custom properties). Likewise, the ZIP file sequencer will be used for generating new content.