fix(loader): allow use without options (messageformat/loader#10)
fix(loader): allow use without options (messageformat/loader#10)

When using the loader without options the getOptions function will return null: https://github.com/webpack/loader-utils#getoptions
As an example, my webpack config for the loader just looks like `{test: /\.lang\.json$/, loader: 'messageformat-loader'}` which
causes this error to be thrown:
`TypeError: Cannot read property 'locale' of null`

SlexAxton/messageformat.js,SlexAxton/messageformat.js,messageformat/messageformat.js,messageformat/messageformat.js