Add framework for Spark Core board support.  The initial commit is a clone of the Maple Mini and still needs Spark customizations

Add freedom-kl25z/minnsh configuration:  This is an experiment to see just how small we and get an NSH configuration.  From Alan Carvalho de Assis.

OS startup logic should not call group_setupidelfiles() if there is no file system support configured

Networking:  Fix backward conditional in test to see if address is in ARP table.  From Max Holtzberg

Networking: If sending out of the subnet, device lookup by IP will fail.  Fall back to ETH0 for now.  From Max Holtzberg

SAMA5 GMAC:  Initial driver check-in is just the EMAC driver forced to compile with the GMAC register definitions

Mov apps/examples/composite to apps/system/composite; convert configs/stm3210e-eval/composite to use kconfig-frontend tools -- untested

SAMA5 EMAC:  Need to pace RX and TX because and RX can result in a TX; Process TX interrupt events before TX interrupt events for the same reason

Move CONFIG_NET_DUMPPACKET from LPC17 and STM32 to commong network drivers.  Automatically enabled CONFIG_NETDEVICES when any Ethernet driver is enabled

SAMA5 OHCI:  Back out a change, the real root cause was a bug in the cache logic so the hack is no longer necessary

SAMA5 OHCI:  Fix some problems with D-Cache coherency and physical addressing related to interrupt endpoints

SAMA5 OHCI:  When UPLL drives OHCI the logically correct divider of 10 does not work;  But a divider of 5 does.  Why?