HP, mana and gold regen, damage conversion

Health, mana and gold are restored every second.
Remaining health is not kept within Stats but instead Minecraft Entity's
health proportion to its MaxHealth is used caculate remaining Dota
health.
When calculating damage, it is first multiplied by a coefficient to be
more Dota-like, e.g. a zombie's attack damage would be 22.5-52.5 instead
of 3-7.