Export file processing

[seanaye]

Allows importing file processing function into other components. Useful if you want to use certain components like the scanner but want to use different premade vue components for file upload i.e. v-file-input from Vuetifyjs

Also updates to babel-preset-env to allow for function exporting

Example

import { processFile } from 'vue-qrcode-reader

export default ({
    ...
    methods: {
        async doSomething (file) {
            this.something(file)
            return await processFile(file)
        }
    }
})