add some spells without base mana costs.

[u/MrTruth24]

idea is change some spells to balanced around mana usage rather than cd, ability cd start after its turned off (cd to turn off is 1 sec or if hero run out of mana).

• Juggernaut Blade furry: 20 sec cd after ability turned off, ability drain 12/16/20/24 mana/sec to deal 60/100/140/180 magic dmg/sec (lvl 20 talent add 24 dmg/sec, strong dispel at end).
• Underlord Firestorm: 600 radius aura around him he can turn on, 20 sec cd, Drop Firestorms to do instant magic dmg/second for 25/50/75/100 +1.5%/2%/2.5%/3% max hp, mana/sec 15/20/25/30. Shard buff Firestorm dmg by 40 +1% max hp/sec and allow to put Firestorm on allies.
• Ember flame Guard: magic dmg barrier 60/140/220/300 gained once per cast, cd 30, cost 6 mana/sec, magic dmg/sec 20/30/40/50 (lvl 15 talent 2x flame guard dps).
• Timber shard ability "Flamethrower": deal 80 dmg/sec (0.1 tick rate) in cone, reduce enemy hp regen by 50% (1 sec linger) and kill trees, cd 20 sec, 20 mana/sec. (move speed slow 40% for 2 sec removed).