Play page UI/UX updates

[Lennevia]

Copying down some updates discussed in office so that they're noted in the right spot:

• Add a link to the play page https://code.thumby.us/play.html under Other Links - this is actually currently referenced in the play page tutorial (oopsies) https://thumby.us/Code-Editor/Share-Games/#play-online-or-on-your-phone
• Bug: the title loading screen of a game will go blank when you resize the window - can still press the button and it'll start playing
• Feature request: Adding a legend for which keys to press on a keyboard for users new to the emulator - perhaps an overlay on the virtual Thumby
• Feature Request: Some type of loading animation when preparing a game. Pulling up Annelid took around 10 seconds on my PC: https://code.thumby.us/play.html?game=Annelid