bugfix: runners reimbursed builders twice
bugfix: digger was cancellable with blocker

The digger had one frame in mid-air, even without having dug through
the terrain already. The digger now moves down a frame ealier as a fix.
The spritesheet hasn't been updated yet, so set_y is called on the sprite.
This can be removed at once when the spritesheet gets updated in a future
fix/feature.
anti-blocker field around goals removed
switched panel and on-play-field code in gamepl_a.cpp
editor debugging leftover removed
bugfix: climbable jumper went through thin platform
hatch opening frame in config file
directional force transmitted by replays and network

This shall remedy the following bug: In a multiplayer team game, if both
players e.g. assign a walker to the same lix to turn her around, two walkers
will be assigned and the lix will end up walking in the same direction as
before. If both players use directional force, this could be amended if the
directional force option was transmitted as well, and the assignment is only
done if the direction of the lix fits. So the later of the two assignments
will be invalid as the directions don't match.
bugfix: bracketed checkmark didn't vanish

Description: I was experimenting with a change to a level. I decided against
it, so I used geoo's replay and the "Extract level" function to retrieve the
previous version of the level. When I went back into the level select menu,
I got the bracketed tick and "Level has been edited" in place of the usual
statistics -- and they remained even after I completed the level again.

Solution: solving a level makes the result always better if
solve.built != old.built, not just solve.built > old.built. Here, built is
the date when the level was built.