* configure.ac: added mmx and cpu detection.
* gegl/Makefile.am:
* gegl/gegl-cpuaccel.[ch]: added from GIMP.
* gegl/gegl-plugin.h: include config.h when compiling in-tree (to
allow checking for USE_SSE in ops.
* gegl/gegl-utils.[ch]: (gegl_malloc), (gegl_free): added malloc and
free that aligns on 16byte boundaries.
* gegl/operation/gegl-operation-point-composer.c:,
* gegl/operation/gegl-operation-point-filter.c:
(process_inner): align allocated buffers on 16byte boundaries to
make it possible to process RGBA buffers using SSE.
* gegl/operation/gegl-operation-processors.c: 
(gegl_operation_class_add_processor): added category SSE that is
autoenabled if sse support is compiled in and detected.
* operations/common/invert.c: (process_sse), 
(gegl_chant_class_init): accelerate the invert operation with vector
maths using SSE.

svn path=/trunk/; revision=2184