Also, levels now inherit a level object

Hero 0 speeds up especially quickly!

Hero 0: Remove cursor, allow wallriding (enable collision detection)

Hero 2: Move RepelHUD to center, ignore self with Area (gravity)

Accidentally put it in the wrong place before

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

This reverts commit 22cf954991.

While on wall, if you press jump, you leap up and away from the wall

If you do so immediately after leaving the wall (<tolerance=.150s), it
still works

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