Accidentally put it in the wrong place before

Within radius 8, attracts heroes with gravity.

In multiplayer, if there is only one hero 1, it is ok, but with more
than one, one hero 1 cannot place walls.

Changing the weight of the objective fixes the weird destroy-the-player
physics.

Also, count how long the objective has been tilted to the right or left,
and put counters there. Slow the game down and display who won when the
count exceeds 100% on either side. Like in overwatch, but with tilting.

This reverts commit 22cf954991.

Unfortunately, apply_impulse seems to have no effect right now. More
research is needed.

There however were some bugs that came with this, so I'm switching to
master to explore this.