Showing binary representation of UTF-8, with colors

In addition to already showing a character's UTF-8 representation in hexadecimal numbers, this commit shows the binary representation as well. The binary digits are color-coded to show which digits signify whether it is a one, two, three, or four-byte UTF-8 representation and which digits are the actual 'payload', i.e. holding the code point's data.

Color coding depends whether the background is light or dark.