Test boids.js
Test (and renamed) boids.js - moveBoid
Fix & Test combinePoints, added pointsRelativeTo

pointsRelativeTo takes a start point and a bunch of other points and
converts the other points to points that are relative to the start
point: e.g. if start point is 10,10 and an "other" point is 12,8 then
the "other" point becomes 2,-2, i.e. what 12,8 is relative to 10,10.

This allows us to get a bunch of target points and figure out what
distances they represent (x and y distances) in relation to a reference
point: i.e. if I want to move from point p to point q, what is p.x - q.x
and p.y - q.y.
WIP: Test applyMovementPipeline (plus logging)

I'm testing out the applyMovementPipeline function, but I'm not done,
and I have some other logging functions I threw in while furiously
debugging; I realized after a while that it would smart to make sure
boids.js is tested (because it will undoubtedly turn out to be broken,
and it was) before I waste time trying to debug other code that's
already tested pretty well.

I either need to do the math and figure out what the two current
movement functions should do to a point based on a couple of neighbours
and a canvas position, or mock out those functions. I think it would be
a tremendous exercise to actually figure out what the flock and arena
movement functions will combine to do to a few different points with a
few different setups. Is it redundant? Yes, in a way, but I'd still like
to have it just so I can sleep better.
Moved point functions to geometry.js
Added temporary logging for debugging.