Improve ship damage / destruction animation

[historic_bruno]

Our ship death animation is quite lacking, even compared to older games like Empire Earth, see ​this video. Currently our ships drop straight down and through the ground when destroyed, the same behavior as structures. It would be more dramatic if instead they listed to one side and slowly sank with other nice eye candy (waves, splashes, whirlpools, bubbles), and instead of instantly disappearing, they could sink to the bottom of the water and remain there, sinking into the mud, perhaps faster than our normal unit corpses so they don't visually interfere.

Similarly to #131 for structures, there should be damage effects like smoke/fire particles for ships.

Create falling animation for ship masts.

This will allow a slower sink/decay time for ships which in turn will allow them to stay sunken on the bottom longer without looking strange (masts sticking out of the water after the ship has decayed below the ocean floor).

• Simple version * (requires the mast to stay attached to the ship)

Separate the ship mast out to its own model (or even just add a bone to the original model). Animate the ship mast to simply snap. It needs to stay attached to the ship in some fashion or the tilting that happens during sinking will look bad.

• Complex version * (does not require the mast to stay attached to the ship)

To accomplish this, the masts will need to be extracted from the existing models (the .blends or other uncompressed formats, not the collada / .dae files). An actor will be created for each mast. The masts will be removed from the original ships and replaced with a prop point. The new mast model will be referenced at the prop point. This might be difficult as some of the old models are not in the .dae format and cannot easily be edited.

One falling animation will be created per mast. An addition mast actor will be created that will reference the new falling animation. This actor will be swapped with the regular mast actor when a ship is "killed".

This ticket is somewhat related to: ​​http://trac.wildfiregames.com/ticket/2461

[leper]

#1921 already improved the ship sinking, but I'll leave this open as some more eye candy would still be nice.

[fatherbushido]

refs r18340

[Freagarach]

Refs. #2461 (contains a patch for improved sinking).