SYSLOG: Add an option to use the syslog'ing device as the system consolution.  This option enables a low-level, write-only console device at /dev/console (similar to the low-level UART console device).  From Pierre-noel Bouteville.

STM32 SPI:  The source clock for SPI 4,5, and 6 should be PCLK2, not PCLK1 (for F411, F427, and F429).  Per David Sidrane.

IPv6 fixes:  Both ICMPv6 autonomous auto-configuration and the ICMPv6 router function appear to be fully functional.

STM32: Add an IPv6 configuration for the STM32F4-Discovery board (witht he STM32-DISCO_BB base board).  Verify that the STM32 Ethernet driver works with IPv6.

Add IPv6 support to network driver skeleton and to SAMA5D4 Ethernet driver (which, unfortunately is still missing address filtering logi)

ICMPv6:  Add logic to behave like a router (if so configured):  NuttX will not send the router advertisement message in response to any router solicitation messages.

ICMPv6 Auto-configuration:  If no router reponds to the Router Solicitation, claim the link local address by sending the Neighbor Advertisement and return success