Make the utf8 -> html code automatic

[epykure]

Try to make the conversion from utf8 to html code for the display in the UI less manual.

The mapping is done here: PyExt.py but maybe there is a better way to do it

UTF8_TO_HTML = {
b'\xe2\x80\x99': "'",
b'\xe2\x81\x80': entities.EntUtf8.CHARACTER_TIE,
b'\xe2\x81\x81': entities.EntUtf8.CARET_INSERTION_POINT,
b'\xe2\x81\x82': entities.EntUtf8.ASTERISM,
b'\xe2\x81\x83': entities.EntUtf8.HYPHEN_BULLET,
b'\xe2\x81\x84': entities.EntUtf8.FRACTION_SLASH,