Added matplotlib.colors to parse named colors

The svg parser will incorrectly parse colors such
as 'green' and 'red' to black. This commit fixes
that by using the code already written in matplotlib.colors
module

pydiffvg/parse_svg.py

@@ -10,6 +10,7 @@ import re
 import warnings
 import cssutils
 import logging
+import matplotlib.colors 
 cssutils.log.setLevel(logging.ERROR)
 
 def remove_namespaces(s):
@@ -70,6 +71,10 @@ def parse_color(s, defs):
     elif s == 'none':
         return None
     else:
+        try : 
+            rgba = matplotlib.colors.to_rgba(s)
+            color = torch.tensor(rgba)
+        except ValueError : 
             warnings.warn('Unknown color command ' + s)
     return color