Add configurable options to defineProperty

[ghost]

Add configurable options to defineProperty allowing you to re-create the object, which in turn allows you to initialize koa-i18n in a request, for instance

app.use( ( ctx, next ) => {
  return i18n( app, {
    directory: `../public/themes/${ctx.state.theme}`,
    locales: [ 'en-US' ]
  } )( ctx, next );
} );

The purpose is to be able to retrieve and access ctx when defining i18n for configurable options.

[coveralls]

Coverage remained the same at 100.0% when pulling 83a394b on fjeddy:master into f88c9ba on koa-modules:master.