previously, loading a display object from a URL would just be bytes, ignoring page encoding, causing a UnicodeDecodeError when json tried to serialize the data. This respects the encoding if the header specifies one.
respect encoding of display data from urls
@fperez, I am going to merge this. But a better demo is to put the page in an iframe like this:
HTML('<iframe src=http://www.google.fr width=600 height=400>')