[oe] Patch for libfann-2.0.0 recipe

[Elvis Dowson]

Hi,
	If we use

inherit autotools_stage pkgconfig

it will install the header files into ${STAGING_INCDIR}. So just to  
keep it neat and organized, Justin and myself thought it best that we  
put it in a subfolder  ${STAGING_INCDIR}/fann, just to keep things  
organized.

You can call it from the code as #include <fann.h> if  you use  
autotools_stage, or if you create the do_stage() method, an ensure  
that the fann library headers get put in the ${STAGING_INCDIR}/fann,  
called it from the code as #include <fann/fann.h>

Elvis