Adjust heating up from energy damage / cool-down

 - NPCs now get heating from energy attacks too
 - heating is reduced significantly for ships larger than Cobra
 - cooling rate to space is reduced quite a bit
 - NPC hullHeatLevel uniform now clamped to 0..1 (fixes shader whiteout)

Mostly cosmetic in normal space, but makes fighting near a star more
dangerous.

Cooling rate and NPC heating may need a bit of fine-tuning.