Add TypeScript support

[Dan503]

The world is moving to TypeScript.

This is still a useful library so it needs to keep up.

I've already made a start on writing out the Types needed for this:

type Callback = (screenSize: number) => void

type SimpleMq<BP> = (bp: keyof BP, cb?: Callback) => boolean
type ComplexMq<BP> = (bp1: keyof BP, bp2: keyof BP, cb?: Callback) => boolean
type ReactToCB = (isActive: boolean, screenSize: number) => void

export interface MqJs<BP extends object> {
	/** Returns `true` if the window size is **less than** the breakpoint size */
	min: SimpleMq<BP>,
	/** Returns `true` if the window size is **greater than** the breakpoint size */
	max: SimpleMq<BP>,
	/** Returns `true` if the window size is **greater than smaller** breakpoint but **less than the larger** breakpoint */
	inside: ComplexMq<BP>,
	/** Returns `true` if the window size is **less than the smaller breakpoint** or **greater than the larger** breakpoint */
	outside: ComplexMq<BP>,
	/** Runs a callback function every time `testMQ` changes from returning `true` to returning `false` */
	reactTo: (testMQ: () => boolean, cb: ReactToCB) => void
}