Refactored README in view of 0.8.0->0.9.0 transition
Added layer dependency note to NTP recipe README
Added fix for dmidecode compilation on systems with make 3.82

That made image-full or image-spi building impossible on such systems,
e.g. openSUSE 12.3. The fix is taken from the dmidecode CVS and is
courtesy of dmidecode developer "khali".