Adds an old-kernel-gcc-hdrs bbclass to provide the include/linux/compiler-gccX.h headers needed by 3.10 kernels when built with newer GCC versions (5, 6 and now 7 with the upgrade to rocko)

dbus: Install an apropriate session bus configuration for geoclue-hybris (which has a setuid bit and owns a session service as root)

connman: Allow send to net.connman.Service by default so that msyncd can work correctly. Removes some warnings from journalctl

Move psplash launch from rootfs to initramdisk. Fixes the infinite reboot time, removes a dirty recipe hack and makes the booting experience slightly smoother