Merge branch '3.21.2019Stuff' into 'master'

Misc is miscellaneous

Mostly simple stuff, but a bunch of changes are aimed at tuning Archmage mana balance a bit more since Disruption Shield is changed and after actually looking at the spells the cost efficiency was pretty silly.  Improving these is fine given how many misc nerfs AM is getting.

Manasurge:  Cooldown considerably reduced, stat scaling increased.  This helps keep it as a good reaction to hitting 0 mana, and the numbers were pretty bad in general.  We should really expand this to work on all the resource mana burn targets.

Thunderstorm:  Mana cost removed.  This adds a nontrivial amount of passive damage through mid game for all builds.

Fireflash:  Mana cost reduced, damage increased.

Chain Lightning:  Mana cost reduced, damage increased.

Mudslide:  Mana cost reduced.

Arcane Vortex:  Mana cost reduced, can now crit.

Stoneskin:  Mana cost decreased.

Glacial Vapors:  Fixed 8 duration, can now crit.  This spell is still pretty bad but at least in theory it sometimes has high damage efficiency maybe..?

Disruption Shield:
- Now gives 100 mana on deactivation, this is to keep the talent as a counter to mana drain albeit in a much worse way
- Deactivation threshold is 10% mana from 25% (not needed at all now?)
- Aegis mana bonus improved
- Can now crit

Aether Avatar:
- Now gains the increased mana pool size as mana
- +25% arcane penetration

Antimagic Zone:
- Cooldown increased
- Silence fixed at 3 duration

Mana Clash:  Cooldown increased.


See merge request !527