Add test dir to include path. Probably useful for the DOMTS stuff.
Add test dir to include path. Probably useful for the DOMTS stuff.

svn path=/trunk/dom/; revision=6894

prepare/netsurf_libdom,dunkelstern/libdom,dunkelstern/libdom,Achal-Aggarwal/libdom,Achal-Aggarwal/libdom,prepare/netsurf_libdom,prepare/netsurf_libdom,dunkelstern/libdom,dunkelstern/libdom,Achal-Aggarwal/libdom,dunkelstern/libdom,Achal-Aggarwal/libdom,Achal-Aggarwal/libdom,prepare/netsurf_libdom,prepare/netsurf_libdom,Achal-Aggarwal/libdom,prepare/netsurf_libdom,dunkelstern/libdom