title: New column in ng2-smart-table created from Object datatype
body: <p>Does anyone know how to create new column from Object datatype ?
  How I able to to do it ?
  Code of my setting and data below for more clearly understanding
  Thanks in Advance!
      private settings = {</p>
  
  <pre><code>columns: {
        firstName: {
          title: 'First name',
          type: 'text'
        },
        lastName: {
          title: 'Last name',
          type: 'text'
        },
        userType: {  
          // This is correct way only when there is string in response from API named - userType
          // But when I'm trying to type something like - userType.value i get an error 
          title: 'User type',
          type: 'text'
        },
  }
  </code></pre>
  
  <p>data from API: </p>
  
  <pre><code>.......
      {
        firstName: 'Jacob',
        lastName: '',
        middleName: '',
        userType: {value: 'superAdmin', display: 'Super Administrator'},
        login: '',
        password: '',
        phoneNumber: '066-233-77-34',
        city: 'Rome',
        address: 'someStreet',
        salary: '0',
      },
  ......
  </code></pre>