NSH library: Extend ifconfig to support 6loWPAN.  Adapt to some changes in configuration variable usage.

examples/ostest: Add tests for pthread_rwlock.  Adding tests to be used to verify the pthread_rwlock lock works

Set the 'exit on error control' and/or 'print a trace' of commands when parsing scripts in NSH.  The settinngs are in effect from the point of exection, until they are changed again, or in the case of the init script, the settings are returned to the default settings when it exits.

Included child scripts will run with the parents settings and changes made in the child script will effect the parent on return.

Use 'set -e' to enable and 'set +e' to disable (ignore) the exit condition on commands. The default is -e. Errors cause script to exit.

Use 'set -x' to enable and 'set +x' to disable (silence) printing a trace of the script commands as they are ececuted. The default is +x. No printing of a trace of script commands as they are executed.

examples/nettest:  If doing loopback, but not using the official loopback device, then use the server should use the configured client IP address

NSH: Fix some warnings about integer/pointer casts of different sizes (probably only effects 64-bit simulation)

Causes build problems and does not follow the coding style.

This reverts commit 87fe31f8.

ieee802154: Removes ieee802154.h references

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

ieee802154/coord: Updates logic to reflect changes in nuttx 802154 code

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

Merged in david_s5/apps-1/david_s5/appsmm-removed-extraneous-comment-from-m-1490711722259 (pull request #71)

apps/mm removed extraneous comment from Makefile

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