[EM] proper Borda implementation

[Jeffrey O'Neill]

Hello,

I'm not sure of the best way to implement Borda with ballots that don't 
rank all the candidates.  Suppose that 4 candidates are running.  With a 
ballot like:
	A B C D
A gets 4 points, B gets 3 points and so on.  But what about a ballot like
	A B
A and B should be treated as above, but what about C and D?  I see two options:

(1) C and D each get nothing.

(2) C and D each get 1.5 points (average of leftover points).

Any thoughts as to which is better?

Jeff