TODO
====
[ ] Sound settings (volume)
[ ] Paper/Plastic rulesets
[ ] Use #private methods, where not yet done (e.g. UI)
[ ] isGameMaster --> isGameHost
[?] player1, player2 --> host, guest
[ ] onConnectionLost --> AI takes over (Need to re-enable player checks I removed)
[ ] .opponentready - change background when other player clicked ready
[ ] Show game screen only, when both players are connected
[?] body.images --> body.background_images
[?] Bgimages fade into each other --> ::before instead of background-image
[!] Refactor to use from/to in messages
[E] Drag from yard: Ship position different before and after moving the div to the table
[?] Ship: Sunk: Mark fields around it as "attacked"
[?] Ship: Show div/image in opponent grid, when sunk
[E] Ship: Too long by 1px?
[!] AI: Find rest of ship, once a hit is landed
[ ] README.md + screenshot
[\] Allow dragging ship back to yard (for rotating)

REFACTOR MESSAGES
=================
message.id --> message.recipient(s)