[PATCH] Chicken should not block units

[elexis]

Since the new pathfinder, units make a big leap around obstructions instead of breaking the formation apart. This is very useful, since units now avoid the forest instead of getting entangled there. But being blocked by chicken near the CC is very hindering, especially in the beginning of the match.

Berries have become passable in r8899, see ​http://trac.wildfiregames.com/changeset/8899/ps/trunk/binaries/data/mods/public/simulation/templates/template_gaia_flora_bush.xml

So I propose to make chicken ghosts too, would help a lot and not really look bad.

[Stan]

Assess the need.

[elexis]

Also makes rabbits passable. Swimming animals like sharks and whale might make sense too. All other land animals are bigger than that and should certainly block in my opinion.

[historic_bruno]

The pathfinder-formation interaction is really broken now, in some cases they are forced to go far out of their way when the formation only needs to adapt a little.

This seems like an OK workaround in this case, and it's not a huge problem with the animals being so small, but ideally they would quickly flee out of the way of approaching units and the units wouldn't stay in such a rigid formation but "flow" around the obstacles.

[wraitii]

In 17166:

Make "no formation" the default setting but keep formations activated to help pathfinding in A19. Use at your own risk. Refs #3505 and #3565.

Also make rabbit, chicken and shark no longer obstruct movement, to further help with pathfinding. These may or may not be udpated later. Refs #3562. Fixes #3497.