- move EXTERNAL_KERNEL_TREE & NO_STRIP from DEVEL to BUILDOPTS
 - remove BUILDSYSTEM_SETTINGS and move DOWNLOAD_FOLDER to DEVEL
 


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@12592 3c298f89-4303-0410-b956-a3cf2f4a3e73