Remove all support for the CC3200 and CC3200-Launchpad.  This was a port that was started but never completed.  What good is partial CC3200-Launchpad board support with no wireless support?

Squashed commit of the following:

    Remove final references to CC3200 from the repository.
    arch/arm/include/tiva:  Remove all CC3200 support.
    arch/arm/src/tiva:  Remove all CC3200 support.
    configs/cc3200-launchpad:  Remove the board support directory.

This commit removes all support and all references to the Spark board and to the CC3000 wireless part.

Squashed commit of the following:

Author: Gregory Nutt <gnutt@nuttx.org>
    Fix a few remaining refereces to cc3000.

Author: Alan Carvalho de Assis <acassis@gmail.com>
    drivers/wireless/cc3000: emove the driver to support CC3000 because it doesn't use the USRSOCKET

Author: Alan Carvalho de Assis <acassis@gmail.com>
    configs:  Remove board support to CC3000 from all relevant configurations.

Author: Gregory Nutt <gnutt@nuttx.org>
    configs/spark:  Removes Spark board configuration.  Still available in the Obsoleted repository.  This is preparation for removal of CC3000 support by Alan Carvalho de Assis.  If there is no CC3000 support, then there is no purpose in supporting the Spark either.

configs/xtrs:  Removed the XTRS configuration This was an unverified port of NuttX to a TRS-80 simulator.  It was removed because (1) it is, as I said, unverified as well as unsupported, and (2) the TRS-80 simulation is a sub-optimal platform.  That platform includes a 16-bit ROM image and only a 48Kb RAM space.

configs/mx1ads:  This commit removes board support for the mx1ads board.  That board support was never completed and I no longer even have the hardware.  The unfinished board support is still available in the Obsoleted repository if anyone would ever like to resurrect it.

configs/nucleus2g:  Remove this board from the configs/ directory.  A snapshot is still available in the Obsoleted repository