added sequencer paths to bpath iterator, This needed to use get/set filename callbacks internally because the sequencer stores dir/file separately.

This means when moving large projects with many images/videos/sounds is possible with 'File, External Data, Find Missing Files'.
- needed so we can put peach animatic, glrenders & testrenders on the dvd.
also datatoc.c - brecht's fixes from apricot.

source/blender/include/BSE_sequence.h

@@ -92,6 +92,7 @@ void update_changed_seq_and_deps(struct Sequence *seq, int len_change, int ibuf_
 struct RenderResult;
 void do_render_seq(struct RenderResult *rr, int cfra);
 
+#define SEQ_HAS_PATH(seq) (seq->type==SEQ_MOVIE || seq->type==SEQ_HD_SOUND || seq->type==SEQ_RAM_SOUND || seq->type==SEQ_IMAGE)
 
 #endif