Fix a handful of additional encoding issues. I don't like patching

cssutils, but cssutils as-is insists on decoding the contents of
@imported files itself.  Another option would be to just encode
everything back into UTF-8 and then let cssutils decode it again, but
that seems even worse than a two-line patch.

src/calibre/ebooks/lit/writer.py

@@ -474,7 +474,7 @@ class LitWriter(object):
             name = '/data/' + item.id
             data = item.data
             secnum = 0
-            if not isinstance(data, basestring):
+            if isinstance(data, etree._Element):
                 self._add_folder(name)
                 rebin = ReBinary(data, item, self._oeb, map=HTML_MAP)
                 self._add_file(name + '/ahc', rebin.ahc, 0)
@@ -483,6 +483,8 @@ class LitWriter(object):
                 data = rebin.content
                 name = name + '/content'
                 secnum = 1
+            elif isinstance(data, unicode):
+                data = data.encode('utf-8')
             self._add_file(name, data, secnum)
             item.size = len(data)
 

src/calibre/ebooks/oeb/stylizer.py

@@ -173,7 +173,7 @@ class Stylizer(object):
             return (None, None)
         data = hrefs[path].data
         data = XHTML_CSS_NAMESPACE + data
-        return (None, data)
+        return ('utf-8', data)
     
     def flatten_rule(self, rule, href, index):
         results = []

src/cssutils/util.py

@@ -840,7 +840,9 @@ def _readUrl(url, fetcher=None, overrideEncoding=None, parentEncoding=None):
 
         try:
             # encoding may still be wrong if encoding *is lying*!
-            if content is not None:
+            if isinstance(content, unicode):
+                decodedCssText = content
+            elif content is not None:
                 decodedCssText = codecs.lookup("css")[1](content, encoding=encoding)[0]
             else:
                 decodedCssText = None