Add additional params to EntityManager constructor

[GGAlanSmithee]

The EntityManagers public API is (subjectively) pretty straight-forward and easy to consume. This is something that I want to preserve. However, there are plenty of room of making the interal operations of it adjustable through some configurations.

Idea

var entityManager = EntityManager(options)

options

An Object (or undefined) of options which drives certain behaviours of the EntityManager.

const options = {
    capacity: number | undefined, // default 1000
    autoAdjust: true | false | undefined, // default false
    lazy: true | false | undefined, // default false
}

options.capacity

The initial capacity (number of entities) of the entity manager.

options.autoAdjust

Wether the capacity (number of entities) should grow / shrink as entities are added / removed. When set to true, the list of entities would;

1. double in size if all enteties are used
2. shrink to 3/4 size if half of all entities are un-used

options.lazy

Wether all entities should be eagerly pre-instantiated (false) or lazily instatiated as an entity is created (true). This is a tradeof of speed vs memory