* gegl/buffer/gegl-buffer-private.h: moved the linear API ..
* gegl/buffer/gegl-buffer-linear.h: into it's own header.
* gegl/buffer/Makefile.am: added gegl-buffer-linear.h
* gegl/buffer/gegl-buffer-linear.c: made all accesor functions take
a GeglRectangle instead of passing width and height as individual ints.
* gegl/buffer/gegl-buffer-iterator.h: improved documentation.
* tests/buffer/Makefile: output which files are only found in output
after running.

svn path=/trunk/; revision=2482