waitpid:  CRITICAL BUGFIX.  Add a reference counting mechansim to prevent wait from using stale memory that was freed by the exiting task

Adds a driver for the PCA9635PW I2C LED driver IC which can be used to control the intensity of up to 16 LEDs.  From Alexander Entinger

OS modules:  Add basic procfs support.  A module registry that will eventually be used to support lsmod

binfmt/libmodule:  Add support for kernel modules.  Initial commit is  just the ELF module support with name changes

drivers/net/telnet.c:  Now works like the loop device.  A new interface called telnet_initialize() registers a telnet session "factory" device at /dev/telnet.  Via ioctl, the factory device can create instances of the telnet character devices at /dev/telnetN to support Telnet sessions.

s/procfs:  The procfs file system can now be configured so that it supports a runtime registration of procfs entries with CONFIG_FS_PROCFS_REGISTER=y

Remove CONFIG_NET_PINGADDRCONF.  This was a uIP way of assigning IP addresses, but is not standard and not a appropriate feature in general.

sched/pthread/: CRITICAL BUGFIX: Logic was wiping out the indication that of the type of a pthread.  Hence, it could be confused as a task.  Found because this was causing a crash when /proc/nnn/cmdline was printed.

include/nuttx/net/netdev.h and several Ethernet drivers in arch/:  Most network drivers to not support statistics.  Those that do only support them when DEBUG is enabled.  Each driver collects an architecture specific set of statistics and there is no mechanism in place to view those statistics.  Thus, the driver feature was mostly useless.  This change standardizes the driver statistics and puts the definition in the common network device structure defined in netdev.h where they can be accessed by network applications.  All Ethernet drivers that collect statistics have been adapted to use these common statistics.

drivers/mtd/mtd/mtd_procfs/c and include/nuttx/mtd/mtd.h:  Add an interface to un-regiser an MTD procfs entry.
drivers/mtd/filemtd.c:  New new MTD conversion layer that will convert a regular file (or driver file) to an MTD device.  This is useful for testing on the simulation using the hostfs.

From Ken Petit

drivers/lcd/ili9432.c:  Fixed errors in orientation. Portrait, RPortrait, and RLandscript should work correly now.  They were displayed mirrored.  From  Marco Krahl

fs/hostfs: Add a special file system for use with simulator that supports access to the host file system from the simulation.  From Ken Petit

size_t should be 64-bits on a 64-bit machine. mmsize_t should be 32-bits (unless CONFIG_MM_SMALL is selected).  This commit backs out the last change to stddef.h

Revert "Add option to specify logical sector size during low level format plus adds some run-time geometry tests.  fs/smartfs: Remove the 'mksmartfs()' code from the kernel 'fs'"

This reverts commit 96faf0fa3251ca10a17daddc728d931be5a206e0.