Allow Component composition about flame

[renancaraujo]

@erickzanardo That coud work. Since my "wrapper" component is a PositionComponent, I think ComposedComponent could be a mixin.
Example of usage:

class MyComponent extends PositionComponent with ComposedComponent {
...

[luanpotter]

I like the idea of a mixin, I'm feeling more and more inclined about replacing this hierarchy of components with mixins in the future, I've already created several of them inside one of my games that could potentially be extracted to flame.

[erickzanardo]

Wouldn't a new component class be better? Like a ComposeComponent or ComponentGroup that wraps how many components you need?

This new class would them be responsible by wrapping these inner components and the orchestration of the calls of render and update.

[luanpotter]

Merged #25