Add support for emoji 😀 to browser

[eligolding]

Emoji are characters, and you can call create_text to draw them, but the results aren’t very good. Instead, head to the OpenMoji project, download the emoji for “grinning face” as a PNG file, convert to GIF, resize it to 16×16 pixels, and save it to the same folder as the browser. Use Tk’s PhotoImage class to load the image and then the create_image method to draw it to the canvas. In fact, download the whole OpenMoji library (look for the “Get OpenMojis” button at the top right)—then your browser can look up whatever emoji is used in the page.