prevent spectators from guessing/clicking

[CWempe]

When we were playing this awesome game it occasionally happend that someone accidentally clicks a word.

Apart from that it worked great when I was kind of the game master who shared the guess mode widow and was the only person to click a word when a team guessed one.
One reason for this was, because some screens did not reload properly.

My proposal:

• spymasters stay the same
• guesser/spectators cannot click a word
• game master can click a word

Alternatively the spymasters are the only ones that can click a word.

Of cause, this should be optional.