Conditional effects and meta/post effects

[Chillu1]

A better solution to dynamic post/meta effects, by instead using conditional logic on runtime, so no state is needed in the effects or meta/post effects. At the cost of a small performance penalty.

Issues/Design choices:

• Should effects store meta condition effects separately? To not type/null check the conditional/non-conditional ones.
• Conditions not inferring the inherited type with generics, forcing more boilerplate code when adding conditions.

Closes #41