Fix subsetting of fonts whose names start with "and" not working

Caused by a bug in the font-family parsing routines of cssutils,
workaround by quoting the family name before passing it to cssutils.

src/tinycss/fonts3.py

@@ -16,6 +16,7 @@
 def parse_font_family_tokens(tokens):
     families = []
     current_family = ''
+
     def commit():
         val = current_family.strip()
         if val:
@@ -37,19 +38,23 @@ def commit():
         commit()
     return families
 
+
 def parse_font_family(css_string):
     return parse_font_family_tokens(tokenize_grouped(type('')(css_string).strip()))
 
+
 def serialize_single_font_family(x):
     xl = x.lower()
     if xl in GENERIC_FAMILIES:
         if xl == 'sansserif':
             xl = 'sans-serif'
         return xl
-    if SIMPLE_NAME_PAT.match(x) is not None:
+    if SIMPLE_NAME_PAT.match(x) is not None and not x.lower().startswith('and'):
+        # cssutils dies if a font name starts with and
         return x
     return '"%s"' % x.replace('"', r'\"')
 
+
 def serialize_font_family(families):
     return ', '.join(map(serialize_single_font_family, families))
 
@@ -65,6 +70,7 @@ def serialize_font_family(families):
 GENERIC_FAMILIES = frozenset('serif sans-serif sansserif cursive fantasy monospace'.split())
 SIMPLE_NAME_PAT = re.compile(r'[a-zA-Z][a-zA-Z0-9_-]*$')
 
+
 def serialize_font(font_dict):
     ans = []
     for x in 'style variant weight stretch'.split():
@@ -83,6 +89,7 @@ def serialize_font(font_dict):
         ans.append(serialize_font_family(val))
     return ' '.join(ans)
 
+
 def parse_font(css_string):
     # See https://www.w3.org/TR/css-fonts-3/#font-prop
     style = variant = weight = stretch = size = height = None
@@ -178,6 +185,7 @@ def parse_font(css_string):
         ans['font-family'] = families
     return ans
 
+
 class FontFaceRule(object):
 
     at_keyword = '@font-face'
@@ -192,6 +200,7 @@ def __repr__(self):
         return ('<{0.__class__.__name__} at {0.line}:{0.column}>'
                 .format(self))
 
+
 class CSSFonts3Parser(CSS21Parser):
 
     ''' Parse @font-face rules from the CSS 3 fonts module '''
@@ -214,4 +223,3 @@ def parse_font_face_rule(self, rule, previous_rules, errors, context):
         declarations, decerrors = self.parse_declaration_list(rule.body)
         errors.extend(decerrors)
         return FontFaceRule(declarations, rule.line, rule.column)
-