apps/examples/elf: Add configuration optionst o support building the hello++4 example that depends upon having uClibc++ available.  From Leo aloe3132.

Enhancements to NSH ifconfig for case of multi-link operation, TUN device and local connections.  From Max Neklyudov.

Add a test of nested signals.  There are no failures to handle signals but neither am I getting any nested signal handling

STM32F429i Disco: (1) Fix a bad return value if the LCD driver is already initialized. (2) The LCD driver initialization is now performed during the early boot sequence.  (3) Increased the size of the message queue from 32 to 64 in the lcd configuration.  From Marco, ocram.lhark@yahoo.com.

apps/examples/nxlines:  Fix missing right bracket that causes compile error when CONFIG_NX_XYINPUT=y.  From Librae.