Mana Bomb upgrades

Mana Bomb will now tell you how much mana the opponents you have hit
have remaining.

Monsters can now mana bomb for more mana depending on level/4.

Monsters that are hit by mana bombs will now cease spellcasting for 1
second per spellpower of the mana bomb, up to 1 minute 39 seconds.
Previously, they only stopped for ten seconds regardless of mana bomb
size.