Remove CONFIG_NET_PINGADDRCONF.  This was a uIP way of assigning IP addresses, but is not standard and not a appropriate feature in general.

SAME70:  Initialization has to be done a little differently because the board has no 32.768KHz crystal installed

SAME70 Xplained: Refresh configuration, enable PROCFS.  Add logic to automatically mount procfs during initialization

Move up_appinit.c to configs/sim/src where it belongs.  Add logic to automatically mount the procfs file system if it is enabled.

All SAMA5 configurations: Refresh configurations, enable PROCFS in all configurations that have CONFIG_NSH_LIBRARY=y, add logic to automatically mount the procfs if it is enabled

Nucleo F303RE: Comment out CONFIG_APPS_DIR

Nucleo F303RE: Add serialrx configuration