fixed BUG-15: book nums missing for parent books in series

BUGs

@@ -1,5 +1,4 @@
-#### BUGS (next-15)
-BUG-15:		http://mara.ddp.net:5000/series/36 -- book num's not showing (b/c books are parent books? in a different series)
+#### BUGS (next-16)
 
 ### DB/back-end
 BUG-2:		series does not deal with calcd_rating... 

templates/books_for_series.html

@@ -39,10 +39,11 @@
 				<td data-sort="{{series.id}}{{"{:02d}0".format( num )}}">
 			{% endif %}
 			{% for s in book.series %}
-				{% if not book.child_ref|length %}
-					{{ SeriesBookNum( s.id, book.id ) }} of <a href="/series/{{s.id}}">{{s.title}}</a><br>
+				{% set num = SeriesBookNum( s.id, book.id ) %}
+				{% if num != None %}
+					{{num}} of <a href="/series/{{s.id}}">{{s.title}}</a><br>
 				{% endif %}
-				{% if SeriesBookNum( series.id, book.id ) == 1 %}
+				{% if SeriesBookNum( s.id, book.id ) == 1 %}
 					<script>
 						{% if book.parent|length %}
 							$('#up-{{book.parent[0].id}}').prop("disabled", true)
@@ -51,7 +52,7 @@
 						{% endif %}
 					</script>
 				{% endif %}
-				{% if SeriesBookNum( series.id, book.id ) == series.num_books %} 
+				{% if SeriesBookNum( s.id, book.id ) == s.num_books %} 
 					<script>
 						{% if book.parent|length %}
 							$('#down-{{book.parent[0].id}}').prop("disabled", true)