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/src/writeimage.c

@@ -218,9 +218,11 @@ void save_image_filesel_str(char *str)
 /* calls fileselect if zbuf is set we are rendering the zbuffer */
 void BIF_save_rendered_image_fs(int zbuf)
 {
-	RenderResult *rr= RE_GetResult(RE_GetRender(G.scene->id.name));
+	RenderResult rres;
 	
-	if(!rr) {
+	RE_GetResultImage(RE_GetRender(G.scene->id.name), &rres);
+
+	if(!rres.rectf) {
 		error("No image rendered");
 	} else {
 		char dir[FILE_MAXDIR * 2], str[FILE_MAXFILE * 2];