hide version for bundled plugins because it's meaningless; for everything else support showing version using git (if about[0] is null)

plugins/af_psql_trgm/init.php

@@ -7,7 +7,7 @@ class Af_Psql_Trgm extends Plugin {
 	private $default_min_length = 32;
 
 	function about() {
-		return array(1.0,
+		return array(null,
 			"Marks similar articles as read (requires pg_trgm)",
 			"fox");
 	}