[sod] Just Belhifet things

[CamDawg]

Noticed this today as I was compiling Belhifet's stats:

• Belhifet has two weapons (bdbelhi1, bdbelhi2) that he swaps between, depending on difficulty. The one for higher difficulties (>= normal) is equal or superior in every way, except that it only does half of the poison damage per hit (1hp/6 seconds) as the lesser one (1 hp/3 seconds).
• Belhifet has explicit immunities (via bdbelhia.itm) to the Fire Storm, Fireball and Lightning Bolt spells. I'm not sure exactly why these are here (preventing being hurt by allies slinging spells indiscriminately?), but it does leave the weird situation where a normal mage Lightning Bolt won't affect him, but the Lightning Bolt from an Avenger druid or the innate from a Stormlord will. I'm not as concerned with Fire Storm and Fireball as he has 100% fire resistance.

For the former I say we just raise the poison damage on the higher difficulty weapon to match the lesser. For the latter we should probably add immunities to Lightning via Avenger/Stormlord/Wand of Lightning OR clone lightning into Yet Another Copy and have his allies use that instead.