This is necessary because one of the three old methods relied on scipy
for some complex problem solving. LEA is generally better for
evaluations.
The downside is that this means evaluations aren't comparable with many
papers, but canonical scoring can be supported using external eval
scripts or other methods.
This is closer to the traditional evaluation method. That uses an
average of three scores, this is just using the bcubed metric for now
(nothing special about bcubed, just picked one).
The scoring implementation comes from the coval project. It relies on
scipy, which is one issue, and is rather involved, which is another.
Besides being comparable with traditional evaluations, this scoring is
relatively fast.
