New Feature: Collapsing roofs

A code limitation that has annoyed players since 1.00 is that roofs cannot be destroyed. This is especially jarring when the rest of the building has already been destroyed, leaving a floating platform that defies gravity and common sense.

I've corrected that. Explosions near walls, or on the roof itself, can collapse portions of it.

• A soldier on a collapsing roof tile will fall down and take damage.
• A soldier below a collapsing roof tile will take damage from the debris.
• How many roof tiles collapse depends on the strength and distance to supporting walls.
• If no supporting wall is found, the entire ceiling comes down.
• Some heavily armoured roofs (in, say, a secret research facility) cannot be collapsed.

For demonstration reasons, Red wounds Buns with maximum collateral damage, and Bob makes a few holes into a factory full of childrenBeta Testers:

https://www.youtube.com/watch?v=MG32dp0d-9A&feature=youtu.be[/video]

• One new item was added for this, item #1727 (Roof Collapse) with the tag 268435456. This is required for internal reasons. Any mod wishing to have this feature requires this item and the connected entries in Explosives.xml and ExplosivesData.xml.
• A new sound and a new animation are also needed.
• It is easily possible to add better animations, or even animations to collapse multiple tiles at once. Knowing the community however, nobody will ever do this.
• No, this will not go into any 2014 stable release patches.
• If we now teach the AI to use explosives differently, we might have a good counter to the cheap tactic of camping on rooftops :crossbones:
• Roofs collapse if they are unsupported. In order to prevent that, one could build additional walls...

This has been added to the trunk in r7614 and is fully savegame compatible. GameDir >= r2174 is required, as new animations and sounds were added. Using a lower GameDir will cause penguins to apply to the police academy.