Added custom ListField icons in bootstrap3.

[todda00]

Add ability to include custom add / remove icons for ListFields.

This can be implemented in either AutoField or by using ListField.

Example AutoField:

<AutoField
  name="athletics.otherSports"
  addIcon={(<i className="fa fa-add-circle" />)}
  removeIcon={(<i className="fa fa-close-circle" />)}
/>

Example ListField:

<ListField
  name="athletics.otherSports"
  addIcon={(<i className="fa fa-add-circle" />)}
  removeIcon={(<i className="fa fa-close-circle" />)}
>
  <ListItemField name="$">
    <NestField>
      <TextField name="sportName" className="col-md-6" />
      <TextField name="yearsParticipated" className="col-md-6" />
    </NestField>
  </ListItemField>
</ListField>

[radekmie]

Thank you!