Merge branch 'bnnmsc' into 'master'

Misc 1.7beta5

Meaningful patch notes in approximate order of relevance:  
  
- Tweak difficulty settings for nightmare (rare spawn rate increased from 6.77%->12.5%, zone level multiplier decreased from 50%->25%)  
- Buff the celestial/radiance tree  
- Give all melee classes that don't currently start with a point in weapon mastery at birth a point in weapon mastery at birth; this also serves to make sure randbosses have the weapon mastery they need  
- Improve Pace Yourself  
- Slightly increase dammod for knives (45% str/45% dex -> 50% str/50% dex)  
- Slightly buff glyphs by making them no longer prioritize yourself before enemies for placement   
- Buff Dawn's Blade  
- Make Vor Pride's special vault have a slightly friendlier layout  
- Remove digging from all vaults that currently require digging  
- Add a fun mechanic to prevent farming of ruined dungeon orbs to get alchemy ingredients  

Mostly irrelevant other changes:  
  
- Make orc summoners and orc grand summoners use psiblades instead of slings, give skeleton assassins resolvers.sustains_at_birth, reduce how many turns mind parasite puts talents on cooldown for, remove object cost multiplier from slazish fens, make stoning poison no_npc_use



See merge request !648