Support of multi accounts files #10

[gustawdaniel]

In this pull request packages are updated:

 fecha                       ^3.0.3  →   ^4.2.0 
 iconv-lite                  ^0.5.0  →   ^0.5.1 
 jschardet                   ^2.1.0  →   ^2.1.1 
 eslint                      ^6.0.1  →   ^6.8.0 
 eslint-config-airbnb-base  ^14.0.0  →  ^14.1.0 
 eslint-plugin-import       ^2.16.0  →  ^2.20.2 
 mocha                       ^6.0.1  →   ^7.1.2 

Support for multi accounts files was added.
Support for single account files was not changed.

Structure of single account json:

{
  type: 'Bank',
  transactions: [
    {
      date: '2010-03-03T00:00:00',
      amount: -379,
      payee: 'SOME £$™€ CHARACTERS'
    }
  ]
}

Structure of multi account json:

{
  "accounts": [
    {
      "name": "Alior GBP",
      "type": "Bank"
    },
    {
      "name": "Revolut USD",
      "type": "Bank"
    }
  ],
  "transactions": [
    {
      "date": "2010-03-03T00:00:00",
      "amount": -379,
      "payee": "CITY OF SPRINGFIELD",
      "account": "Alior GBP"
    },
    {
      "date": "2010-04-03T00:00:00",
      "amount": -20.28,
      "payee": "YOUR LOCAL SUPERMARKET",
      "account": "Alior GBP"
    },
    {
      "date": "2010-03-03T00:00:00",
      "amount": -421.35,
      "payee": "SPRINGFIELD WATER UTILITY",
      "account": "Alior GBP"
    },
    {
      "date": "2016-05-31T00:00:00",
      "payee": "Authorization sms",
      "amount": -0.2,
      "category": "Services",
      "subcategory": "Financial",
      "account": "Revolut USD"
    }
  ]
}

[spmason]

The changes look mostly fine, thanks for contributing. There's just some cleanup to do and I think the date-format-guessing needs to be removed

[spmason]

It seems a bit risky to say that any dateStr that includes a ' is a US date format

[gustawdaniel]

Is there any better proposition? This code do not breaks compatibility but is open also for other date format, that I am using.

[spmason]

Per #26 you can pass in a dateFormat option to control how the dates are parsed. us is only supported for backward compatibility