Input redundancy computed incorrectly for k=1

[austin-marcus]

This section causes the input redundancy of a single-variable constant function to be erroneously calculated as 0, when it should be 1.

Example:

from cana.boolean_node import BooleanNode as BN

print(BN(k=1, outputs=[0,0]).input_redundancy())
print(BN(k=1, outputs=[1,1]).input_redundancy())
print(BN(k=1, outputs=[0,1]).input_redundancy())

produces:

0.0
0.0
0.0

and I believe it should be:

1.0
1.0
0.0

[austin-marcus]

I believe Felipe's fork already has a fix for this.

[austin-marcus]

Resolved by #30.