title: Add Icons dynamically to ngx-datatable
body: <p>I have a requirement for adding icons dynamically to the rows of a ngx-datatable in my Angular 4 code. </p>
  
  <p>Just to give a brief of what I'm trying to achieve:
  One column of my ngx-datatable would contain a Boolean value, either true or false, which is of course, returned by a service. In place of true I need to display a glyphicon-ok and on the other hand, in place of false I need to display a glyphicon-remove.</p>
  
  <p>I searched all over the internet but can't find a proper way for doing so. Any suggestions anyone?</p>