-pov max trace level (ray depth)
-pov radiosity importance sampling
-Higher Radiosity samples count (allows Halton sampling)
-pov pretrace_start / pretrace_end
FIXED
-incomplete tooltip for pov low_error
-sky_sphere mapping options:
-world sky gradient to follow pov coordinate system
-Skysphere rotation made independant from camera
-generation of skysphere with image map and BlendSky will just consider the texture for now.

All issues reported here 
http://projects.blender.org/tracker/?func=detail&atid=469&aid=23145&group_id=153
by Constantin Rahn, except Layer selective export, adding it to maydo list