apps/examples/elf:  Extend the ELF program module demo so that you can use compressed ELF programs with CROMFS.

Remove canutils/libuavcan and examples/uavcan.  libuavcan has not built for a year or so.  The basic problem is that as NuttX advances, the old frozen versino of libuavcan has become absolute because it violates the portable POSIX OS interface.  No one is maintaining the port so there is no alternative but to remove it.

  - The maximum block size is now configuration setting in order to give finer control over memory usage.
  - The compression/decompression buffers have been moved out the stack and are now global variables.  This eliminates the need to set large stack sizes to use this utility.
  - Added semaphore protection of all global variables for the case of the FLAT or PROTECTED builds.  Unlike the KERNEL build, the same global variables will be used by each instance of the LZF utility.  If you want thread safety, then you must either (a) serialize all access to the global variables, or (b) pack the global variables into a structure and allocate that structure on each execution of lzf_main().

apps/examples/nsh and posix_spawn:  Must not call exec_setsymtab() directly.  That is a non-POSIX internal OS interface.

apps/examples/lzf:  lzf_compress() now expects the hash table as user allocated input parmeter rather than declaring the huge array on the stack.

apps/system and wireless:  Applications should use the standard clock() interface, not the internal NuttX clock_systimer() interface.

apps/examples/netloop:  Update network loopback example so that it can be used to test TCP KeepAlive.

    apps/examples/ft80x:  Fix some errors in co-processor demos.
    apps/examples/ft80x:  Correct an error in the spinner demo.
    apps/examples/ft80x:  Change some unimportant warnings to informational output to reducing debug output.

    apps/examples/ft80x:  Fix some size calculations.  Add option to disable primitive tests... just too boring to have to watch over and over again.
    apps/graphics/ft80x:  Fix a typo in backlight fade logic; Fix error in formmatted display light debug dump output.
    apps/graphics/ft80x:  Fix some warnings when debug features are enabled.

apps/netutils/tftpc:  This commit modifies the TFTP client functions to use a data read/write callback instead of a file.This allows TFTP to write to arbitrary destination (in my case, a MTD device - for firmware update).  Two new functions are introduced for this, named tftpget_cb and tftpput_cb. They are just made of most of the existing code.  The previously existing tftpget/tftpput functions are now wrappers on the new ones, with callbacks that read/write from files, so my modifications are backwards compatible with existing applications, eg the associated nsh commands dont need to be changed.

apps/graphics/ft80x:  Add controls for enabling/disabling the audio amplifier; Add general interfaces for controlling FT80x GPIOs.

apps/graphics/ft80x:  Add basic support for GPIO and configuration for eventual support of FT80x GPIO audio shutdown controls

apps/graphics/ft80x:  Add interface to play midi sounds; apps/examples/ft80x:  Add an example using stencils.

apps/graphics/ft80x and apps/examples/ft80x:  Fix some compile issues with other configuration options are selected.

apps/graphics/ft80x:  Add more touchscreen interfaces.  apps/examples/ft80x:  Add an interactive example using buttons, keys, and touchscreen input.

apps/graphics/ft80x:  Add interfaces to control the backlight.  apps/examples/ft80x:  Fade the display on and off between each example.