DataTable Column sortField is ignored

[acrimi]

I'm submitting a ... (check one with "x")

[x] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57

Plunkr Case (Bug Reports)
https://plnkr.co/edit/I2F0uj?p=preview

Current behavior
The sortField property of Column is ignored in DataTable, sorting is always done according to the value of 'field'

Expected behavior
Sorting should be done by the value of sortField when provided

Minimal reproduction of the problem with instructions
In the plunker, clicking the Sortable Field column should sort the rows in ascending order as Little, Medium, Big (and reverse for descending) according to their numericValue values which are 1, 500, 1000 respectively. Instead the rows are still sorted alphabetically Big, Little, Medium and sortField is ignored.

• React version:
  16.6.0

• PrimeReact version:
  2.0.0-rc.1

• Browser:
  all

• Language:
  all