Fixes issue #29 and allows optional fields to be omitted during object creation

[ianberryman]

Address issue #29 by adding default value to discretionary data field and all "required: false" fields. Default value is space-filled to field width.

[waldyrious]

I suppose removing the newline at the end of the file was not intentional. Could you put it back in?

[waldyrious]

While we're at it, it would be nice to add the file-ending newline here too.

[waldyrious]

@berryman17 thanks for this, I hit the same issue myself.

Could you please add a test to test/entry.js to cover this change? Something like this, for example:

it('should create an entry even if optional fields are missing', function(){
  var entry = new Entry({
    receivingDFI: '081000210',
    DFIAccount: '12345678901234567',
    amount: '3521',
    transactionCode: '22',
    individualName: 'Glen Selle',
  });
  entry.generateString(function(string) {
    console.log(string);
  });
});

This fails on current master, but it should pass with this PR.

[ianberryman]

Thanks for the review @waldyrious I've committed some changes to address your requests.

[waldyrious]

@joaopaulofonseca can you take a look when you get the chance? This would be useful for us, as we discussed previously (to avoid having to pass empty strings in these fields).