Resolve #15: Convert original boolean/number values if set flag convert true

[alexeymarunin]

I tried to resolve #15

const schema = {
	id: { type: "number", positive: true, integer: true, convert: true },
	name: { type: "string", min: 3, max: 255 },
	status: { type: "boolean", convert: true }
};

const data = { id: "5", name: "John", status: "1" };
console.log(v.validate(data, schema), data);
// Returns: true { id: 5, name: 'John', status: true }

[coveralls]

Coverage decreased (-0.8%) to 99.16% when pulling 3344b12 on alexeymarunin:master into a5f2b05 on icebob:master.

[alexeymarunin]

@icebob is it any problems to submit the request?
This feature is important for our project

[icebob]

Yes, because it is a breaking change. Because it modifies the original object.

[icebob]

#94