Add boolean decorator which defaults to true

[gtnx]

With current boolean implementation, default value is false. It'd be nice to control this.

[davidbonnet]

Defaulting a boolean to false is a natural default, akin [] for an array, {} for an object, and so on.

Realue’s decorator design guideline is to be modular and to set behavior from props as much as possible.

Should there be a different default value wanted, the defaultValue decorator can fulfill that:

const BooleanComponent = compose(
  defaultValue,
  boolean,
)(({ value }) => <span>{value ? 'True' : 'False'}</span>)

// Sets `defaultValue` to `true` and renders <span>True</span>
<BooleanComponent defaultValue />