add jpeg2000 (#828)

kindlecomicconverter/comic2ebook.py

@@ -832,8 +832,7 @@ def chunk_directory(path):
     level = -1
     for root, _, files in os.walk(os.path.join(path, 'OEBPS', 'Images')):
         for f in files:
-            if f.endswith('.jpg') or f.endswith('.jpeg') or f.endswith('.png') or f.endswith('.gif') or \
-                    f.endswith('.webp'):
+            if getImageFileName(f):
                 newLevel = os.path.join(root, f).replace(os.path.join(path, 'OEBPS', 'Images'), '').count(os.sep)
                 if level != -1 and level != newLevel:
                     level = 0