Added Dell U2713H to non-working list

[wbednarski]

Dell U2713H doesn’t work on the latest OS X (10.11.6) and MBPr (MacBook Pro Retina, 13-inch, Early 2015).

It can prob BR and CR values correctly, but can’t set them. Sliders in the menu bar have no effect on monitors BR or CR.

[dmilith]

Dell UP3216Q - also doesn't work. Causes lockdown of IO