Allow more callbacks for incoming data from the emulator

[halemmerich]

Needed for full functionality of espruino/BangleApps#3399

[gfwilliams]

Thanks - just merged and added comments. Looks like you could have used the rxCallback but you'd have had to have split the lines up

[halemmerich]

runapptests.js actually uses the consoleOutputCallback to suppress the output for full lines when the interactive console is active since then every single character is output from the rxCallback. That would otherwise double the emulator output in the terminal.