apps/fsutils/mkfatfs:  When fsutils/mkfats was split off from the operating system, there were a few dangling things left.  Some references to functions in the OS (which are not available in the protected and kernel modes) and several types and function prototeypes that don't exist is apps/fsutils/mkfatfs.

Adds i8shark, a sniffer "adapter" that captures all 802.15.4 traffic, packages it into a Wireshark ZEP packet, and sends it to a host running Wireshark.

Approved-by: Gregory Nutt <gnutt@nuttx.org>

i8sak: Changes 'notif' to 'primitive' corresponding to the changes in the Kernel

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Fixed misprint in cmd_wget

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Fixed i2ctool write operation in `no restart` mode (flag `-n`).

Approved-by: Gregory Nutt <gnutt@nuttx.org>

It seems that I2C driver has changed a bit since i2ctool was written,
so now i2ctool sends repeated start even if `no restart` flag (-n)
was passed to it.

include/netutils/netlib.h:  Add definitions needed when only local Unix domain sockets are supported.

Fix parsing of empty strings when CONFIG_NSH_CMDPARMS is not defined.  Problem noted by Juha Niskanen.

nshlib:  df command no long uses the non-standard OS interface foreach_mountpoint().  No simply cats /proc/fs/blocks or /proc/fs/usage.

nshlib:  mount command no long uses the non-standard OS interface foreach_mountpoint().  No simply cats /proc/fs/mount when there are no arguments to the mount command.

This commit removes the ping6 command from NSH and replaces it with the apps/system/ping6 built-in command.  The NSH ping6 command had to be removed because it violated the portable POSIX OS interface.  The apps/system/ping6 command uses the sem-standard IPPROTO_ICMP6 socket interface.

Squashed commit of the following:

    apps/system ping and ping6:  Fix a backward test.
    apps/system/ping6: ping6 logic now builds without error.
    apps/system/ping and ping6:  Minor clean-up to configuration settings.
    apps/system/ping6:  Minor clean-up to be able to configure CONFIG_SYSTEM_PING6
    apps/nshlib:  Remove support for ping6 from NSH.
    apps/system/ping6:  Add IPPROTO_ICMPv6 ping6.  Initial commit is simply a clone of the IPPROTO_ICMP ping logic.
    Rename CONFIG_NET_ICMPv6_PING to CONFIG_NET_ICMPv6_SOCKET.

This commite eliminates the ping command from NSH and replaces it with a ping 'built-in' at apps/system/ping.  The original NSH version of ping violated the portable POSIX interface and, hence, had to be removed.  The new system/ping command uses the new IPPROTO_ICMP AF_INET datagram sockets to implement ping.

Squashed commit of the following:

    apps/system/ping:  Fix some timing issues.
    apps/system/ping:  A few timing related corrections.
    apps/nshlib:  Remove support for the NSH 'ping' command.  The implementation of that command violated the portable POSIX interface and has been replaced with a ping 'built-in' command at apps/system/ping.
    apps/system/ping:  Add larger payload.  Verify content of echoed payload.
    apps/system/ping:  Various fixes for a clean compile
    system/ping: Add new build structure for system ping command.

    apps/fsutils/mkfatfs:  New user-space fatfs appears to work fine.
    apps/fsutils/mkfatfs:  Move mkfatfs from the OS to here.  Not fully integrated on the intial commit.

examples/alarm: add options for reading alarm value and canceling it

Approved-by: Gregory Nutt <gnutt@nuttx.org>