Adds some crazy useful mixins to every pug template.

+Component(name, options = {})

+Component("Name", { title: "Hello", text: "world" })(text="you" variant="new")
	p So fancy, isn't it.

is the equivalent to:

!= component("Name", { content: "<p>So fancy, isn't it.</p>", title: "Hello", text: "world", variant: "new", attributes: { text: "you", variant: "new" } })

So basically we do:

mergedOptions = Object.assign(
	{},
	attributes,
	options,
	{ content: block() }
)

and then:

!= component(name, mergedOptions)

+Capture(key, callback = null)

+Capture('paragraph')
	p Hello world

is the equivalent to:

- capture('paragraph', '<p>Hello world</p>)

For a documentation of capture and component see @stageny/base.