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/flipnclick-pic32mz:  Switch the serial console to UART4.  Clean up some minor issues the LED options.
    configs/flipnclick-pic32mz:  Add support for two on-board buttons:  T1 and T2.
    configs/flipnclick-pic32mz:  Adds basic board support for the Mikroe Flip&Click PIC32MZ board.  Initial commit is just the configs/pic32mz-starterkit with some name chanages.

    configs/flipnclick-sam3x:  Add support for the 4 user-controllable LEDs on the board.
    configs/flipnclick-sam3x:  Add board support for the Mikroe Flip&Click SAM3X.
    configs/arduino-due:  Update this old configuration so that it is structured a little more like recent board support.

arch/arm/src/lpc54628:  With these changes, the LPCXpresso-LPC54628 NSH configuration is fully functional.  Also adds a README file for the board.

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.

    BCM2708:  Add enough infrastructrue (more stubs) to get a clean compilation of the Pi Zero configuration (with many undefined things at link time).

    BCM2708:  Add basic interrupt handling logic

    BCM2708: Add interrupt register definitions.

    BCM2708:  Add irq.h header file

    BCM2708/Pi zero:  bcm_boot.c and bcm_memorymap.h now compile.  Added pizero linker script.

    BCM2708/Pi Zero:  Add Make.defs needed to build.

    arch/arm/include/bcm2708, arch/arm/src/bcm2708, configs/pizero:  Add some basic build and configuration logic.

    configs/pizero:  Add some basic structure of the Rasperry Pi Zero port.

    Created directory configs/pizero.  Nothing there now but a README.txt file.

    Add initial boot.c and memorymap.c files
    Author: Alan Carvalho de Assis <acassis@gmail.com>

    Add AUX/UART/SPI registers definition
    Author: Alan Carvalho de Assis <acassis@gmail.com>

    Pizero GPIO registers
    * Initial commit to add GPIO definitions
    * Add remaining GPIO registers definition
    Alan Carvalho de Assis <acassis@gmail.com>

    BCM2708 memory map:  Add VBASE defintions; fix VCSDRAM address per Alan; move all virtual address to the bottom of the file to avoid confusion -- top is all physical address; bottom is all veritural address.

    Add initial memory map to BCM2708/BCM2835
    Alan Carvalho de Assis <acassis@gmail.com>

configs:  Add readme for B-L465E-IOT01A Development kit.  This port is currently under consideration (but may not actually happen)

I discovered a problem in the file drivers/serial/serial.c concerning the function uart_close(…). In the case that a serial device is opened with the flag O_NONBLOCK the function uart_close(…) blocks until all data in the buffer is transmitted. The function close(…) called on an handle opened with O_NONBLOCK should not block. The problem occurred with a CDC/ACM device.

Revert "Add a placeholder for nucleo-64 boards.  Currently these are in various directories nucleo-f303re, nucleo-f334r8, and nucleo-l476rg but need to be consolidated here because these are all the same boards."

This reverts commit 935cc4e3.

Add a placeholder for nucleo-64 boards.  Currently these are in various directories nucleo-f303re, nucleo-f334r8, and nucleo-l476rg but need to be consolidated here because these are all the same boards.