Mark all "DONE" features as done for all drivers

Turns out my assumption about DONE was incorrect:
http://lists.freedesktop.org/archives/mesa-dev/2014-August/066525.html

So there appears to be no difference between "DONE (all drivers)" and
"DONE".
Add colspan to WIP and unknown status

This should clarify that the WIP/status is for the feature generally,
not for for a specific driver.