Refactor BrainBtnPanel

[supermario]

@benkitzelman not sure if I missed something, but couldn't see why MessageBus was needed here...

I've refactored assuming it was just inexperience with React, but I could have assumed wrong... (if so, sorry! 😨 )

Check it out and let me know if it makes sense or not.

Also minor change using React's refs feature instead of DOM querying.

Señor @owenbyrne may be interested also...

[benkitzelman]

@supermario as each team has two buttons - the message bus was used to communicate between buttons for a team - ensuring that only one brain for a team is active....

i.e. User clicks on Brain for team Blue, then clicks on Bot for team Blue - both buttons should not be active. There might be a better way to handle this - but I remember you mentioning that the MessageBus was used for communicating between components

[supermario]

@benkitzelman ah sorry, so that's what I missed.

In this case given PlayerBrainPanel contains all the buttons, perhaps we could enforce the click logic at that level.