Fix two bugs when providing options to new File() and new Batch()

[crotger]

Hey there, we're using this for a banking partner that has an alphanumeric (instead of numeric) immediateOrigin value and company ID value. I went to override these values in the schema by using the options.header and options.control values in File and Batch but discovered a couple of bugs there.

Essentially my code looked like this:

const FILE_OPTS = {
  file: {
    header: {
      immediateOrigin: { type: "alphanumeric" },
      // ... other header settings
    }
  },
  batch: {
    header: {
      //... header settings
    },
    control: {
      //... control settings
    }
  }
}

let file = new File(FILE_OPTS.file);
let batch = new Batch(FILE_OPTS.batch);

First, that since the code was using _.merge, the default settings overwrote the ones I passed in, so the type of immediate origin ended up staying as "numeric".
Second, _.merge mutates its input, so my FILE_OPTS constants were changed to the nACH2 defaults.
Third, the code in batch/index.js was using the "header" setting for the control options.

I fixed that in our fork by using _.defaultsDeep instead of _.merge, providing a new empty object to avoid mutating whatever the user has passed in to the constructor, and corrected the typo in the batch options setting to use options.control.

[crotger]

this line was checking for options.control but loading options.header if it was set.

[crotger]

passing an empty object as the first argument to defaultsDeep ensures it creates a new object for these settings instead of mutating options.header.