examples/serialrx: Add configuration options to print the bytes received

mksmartfs: Move into apps/fsutils from kernel, now uses only open and ioctl.  Add configuration option to supported multiple root directories.  From Ken Petit

examples/smart-test:  Adds a circular log type test for SMARTFS wear level code testing.  From Ken Petit

nshlib: Now that NuttX automatically converts block to character devices, the implemention of the DD command no longer has to muck with block to character conversion

drivers/mtd/smart.c  Fixed SmartFS wear level error that occurs when the logical sector size is too small to save all wear level status bytes in a single sector.  Logical sectors 1 and 2 were simply not being allocated and then the read_sector and write_sector routines were failing.  From Ken Petit

Uavcan

Nucleo F303RE: Move C++ initialization from configs to apps/platform

canutils/uavcan: Update default configuration

examples/can: Add missing configuration options

examples/media: Need to update position before seeking; handle the too-many-error case more gracefully

handle when CONFIG_READLINE_MAX_EXTCMDS == 0