catch + and - as sort operator

edit.py

@@ -76,9 +76,13 @@ def sort_clips(edit, sort):
     for clip in clips:
         clip['index'] = idx
         idx += 1
-    reverse = sort.startswith('-')
+    if sort.startswith('+'):
+        reverse = False
+        sort = sort[1:]
+    elif sort.startswith('-'):
+        reverse = True
+        sort = sort[1:]
     last = '' if reverse else 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'
-    sort = sort.lstrip('-')
     if sort == 'manual':
         s = clips
         if reverse: