2011-02-20 dman

== Feature changes ==

Removed constraint on image-field-must-be-multiple.
  Single-value fields mean that only the cover page will be processed.

Fixed behavior on one-page PDFs - previously they would not process correctly.
  
Deleting or replacing pdf original should also delete/rebuild the derived images

== Internal changes ==

Minor PHP-strict fixes.

Added watchdog logs before processing.

Shifted processing from hook_file_insert into hook_nodeapi
  Deleted function pdf_to_imagefield_file_insert()
  Added function pdf_to_imagefield_file_insert()

Added utility function to check if a node had p_t_i settings on its filefields
  pdf_to_imagefield_source_filefield()

Renamed 
  pdf_to_imagefield_save_image($filename, $path)
  to  
  pdf_to_imagefield_save_file($filepath)

Renamed internal variables to be more explicit. 
Sometimes $pdf was referring to the queued job, sometimes to the file data object.
Named the field definition objects explicitly so it was always clear whether 
$field is referring to 
- the source data field name, 
- the source data field cck definition, 
- the destination data field name or definition.