So! Finally time to work on finishing render pipeline project.

This commit brings back:

- Field Render
- MBlur Render (old style)
- Border render with or without cropping

Note: Field Render is not supported in Compositor yet. Blurring or filter
will destroy field information.
Both MotionBlur as Field render are done before Compositing happens.

Fixes:

- The "Save Buffers" option only worked on single frame renders, not for
  Anim render.
- Found an un-initalized variable in Render initialize... this might have
  caused the unknown random crashes with render.

Code restructure:

Cleaned up names and calls throughout the pipeline, more clearly telling
what goes on in functions.
This is visible in the updated first image of the Wiki doc:
http://mediawiki.blender.org/index.php/BlenderDev/RenderPipeline

source/blender/blenkernel/BKE_object.h

@@ -74,6 +74,7 @@ struct Object *copy_object(struct Object *ob);
 void expand_local_object(struct Object *ob);
 void make_local_object(struct Object *ob);
 void set_mblur_offs(float blur);
+void set_field_offs(float field);
 void disable_speed_curve(int val);
 
 float bsystem_time(struct Object *ob, struct Object *par, float cfra, float ofs);