XP rework

[DaloLorn]

Per the Discord to-do list:

• Revamp the XP system to scale off a flagship's base combat strength instead of its size. (Also let flagships get a little bit of XP for killing support ships!)

Most of it seems fairly straightforward. Take the combat strength of a ship, and make that its XP value (and, per the old system, the amount of XP needed for a flagship to reach level 1). Multiply the XP gains by the victim's fleet efficiency, divide it by the killer's own efficiency... simple.

However, there is a catch.

Any ship with support command has access to combat strengths greatly in excess of their design's predicted BCS. Take Mystic's Alipha carriers from this week's SR match, for example. They probably have a BCS rating of 0, because I don't think they had any weapons... but they still reached combat strengths in excess of half a million. At a BCS of 0, this would effectively make them worth 0 XP (though their support cloud would certainly make up the difference!), and allow them to gain +INFINITY levels the first time they killed anything. Not acceptable.

[DaloLorn]

Apparently, the last time I considered this issue, I estimated that a support ship was likely to average a BCS of 5 for every unit of support capacity.

... Until the support ships got obscenely large.

Still, this seems like a fair starting point for determining how much XP a carrier should need to level up.