noticed some strange code, added XXX FIXME.

- metaballs with no supported elements would give an error. no they are skipped.

Lower Delay will rise errors when rendering big images. 
My system Win7 64 (slow HD) reports following error on lower Delay: 
---
Reached EOF while decoding PNG
Cannot open input file
Cannot create backend data
Unknown fileformat
---

Maybe Delay should be bound to the imagesize. Or is there a better solution to wait for povray to finish the writing?

Thanks Campbell

Changed texture scale factor to a better match. Not perfect yet, since user still has to correct scaling by offset.

Commented out a forbidden scene property change. There might be others. We need to find a proper way to translate blender properties to pov ones that are different but achieve the same purpose 

- Automatic indentation in Pov file
- Added "command line switch". (Option to set some command line parameter)

-POV file formatting improvement with UI option and function to handle all tabs/spaces indentation (big clean up)
-use of quote characters made more consistent.

Added some formatting of the pov files and some UI tweaks made by Constantin Rahn (Thanks!). Also the version number had not been updated for a while, I don't know about API number

-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

fixed two typo errors and a compatibility for gamma syntax

Updated pov 3.7 Version directive to keep up to date with the latest beta and added some clean up function for hyphen and dots in object names to get them accepted by pov.

- be explicit with exceptions. new exceptions can be accounted for as needed
- self._process was being checked for None, this should never happen, if it does then that is a bug and should be dealt with separately.