Allow players to have multiple votes.

[shacknetisp]

The discussion about this is here, it wasn't submitted as an issue yet: http://redeclipse.net/forum/viewtopic.php?f=4&t=688

[bonifarz]

Just to summarize some points from the forums:

• players could vote once for each suggested game (maybe show checkboxes)
• suggesting multiple games should be limited (e.g. clears all your previous votes)
• consensus? Some might prefer to allow only one vote per player

[alchzh]

:arrow_up: Bump!
Honestly, if this doesn't take too much work, this should be good.
This prevents a terrible mode & map (i.e. freestyle-instagib) from winning due to the other people being split on other ideas.

[restcoser]

agreed, this is a good idea (i think there should be a server var to switch the behaviour tho)

(just wanted to write tho, freestyle instagib is great :( leave it alone! :3)