Reorganized Water & Ice trees and buffed the early spells

1.6b4 typos n misc

fixed sunburst tgts.  
fixed lightning breath to actually rng.avg dam.  
added average dam to tooltips of some rng.avg lightning sills.  
curse of nightmare particles more transparent.   
fixed typos.  

See merge request !560

This reverts commit dbe75234.

Afflicted+predator

Mindrot fix.  
Creeping Darkness hits target tile.  
Predator revision: https://imgur.com/a/Tv89YRZ

See merge request !558

Blighted Summoning Tweaks

- All summons get bone shield and more Spellpower.
- Summoner Summons and Necro Minions also get corrupted talents
- All other summons also get blight conversion and VD.
- is_nature_summon tag added for summoner summons.
- summon_count handled innately in actor.lua (bonus counts may still be added e.g. alch golem)

See merge request !553