Don't use spread operator for Objects

[Iñaki Baz Castillo]

const _options = { ...defaultOptions, ...options };

/xxxx/node_modules/pick-port/index.js:51
	const _options = { ...defaultOptions, ...options };
	                   ^^^

SyntaxError: Unexpected token ...

Spread operators it's not defined inES6 and it fails in Node 6 and 8:

• https://stackoverflow.com/questions/40066731/node-v6-failing-on-object-spread
• http://node.green/

[Iñaki Baz Castillo]

Instead, use Object.assign. Also, let's avoid creating a ugly _options variable:

options = Object.assign({}, defaultOptions, options);

[José Luis Millán]

Addressed in 0.0.3. Thanks @ibc!