Remove more debugging stuff

src/wireviz/svgembed.py

@@ -12,12 +12,10 @@ def embed_svg_images(filename_in: Path, overwrite: bool = True):
     filename_in = Path(filename_in).resolve()
     filename_out = f'{filename_in.with_suffix("")}.b64.svg'
     images_b64 = {}  # cache base-64 encoded images
-    num_images = 0   # just for debugging
     re_xlink=re.compile(r"xlink:href=\"(?P<URL>.*?)\"", re.IGNORECASE)
     with open(filename_in,'r') as file_in, open(filename_out,'w') as file_out:
         for line in file_in:
             for xlink in re_xlink.finditer(line):
-                num_images = num_images + 1
                 imgurl = xlink.group('URL')
                 if not imgurl in images_b64:
                     if not Path(imgurl).is_absolute():  # resolve relative image path