Fix warnings in USB MSC when compiled for a high speed device; also fix USB MSC default VID/PID configuration

Suppress attempts to manage USB trace if the USB MSC example is built as an NSH built-in application.  In that case, USB MSC does not do a good job managing trace data and gets in the way of other things that can do a better job (like NSH or the USB monitor).

DHCPD: Fix calculation of lease address.  Bad logic causes repeated assignment of the same IP address.  SourceForge bug #21 from Paolo Messina.

Fix UG-2832HSWEG04 landscape.  Add reverse landscape support to UG_2864AMBAG01 and UG-9964HSWAG01.  Fixe NXHELLO default colors for 1-bit mono modes

Add support for the UG-2843HHSWEG04 OLED and for the SAM4L Xplained Pro OLED module that uses that OLED.

Straighten out issues about who calls C++ initializers with CXXTEST or HELLOXX are built as NSH applications; Add an ofstream test to CXXTEST suggested by Michael; Update many defconfig fiels to that they set configurations to handle C++ constructors just as before these configuration changes

Remove CONFIG_XYZ_BUILTIN configurations, replace with the single CONFIG_NSH_BUILTIN_APPS.  Add SAM3/4 sam_periphclks.h which is just a header file that includes the right header file.  Misc SAM3U-EK cleanup

Add missing NSH configuration settings.  Correct some conditional logic for STM32 FALSH pre-fetch settings.  From Lorenz Meier

Add apps/examples/slcd, Remove USB from STM32L-Discovery, LSE support for the STM32 L family, some STM32L-Discovery LCD debug changes

apps/examples/helloxx entry point name was mangled when built as an NSH builtin; plus some README updates