It seems that on linux only inside a makefile the parameter after the echo
command gets printed if no single quoted sting comes afterwards so I had
to switch to single quotes such that I can use the parameter.

Force interpretation of backslash escapes with the parameter -e of echo.
Switch to a lighter blue because on certain terminals default blue is
hard to read on black background.

 - px4_add_module now requires MAIN
 - px4_add_library doesn't automatically link

The calls have not been updated as the CI target has been.

This is required for generating documentation

Depending on the CMake version when we are configuring it emits a
warning about deprecation of CMAKE_FORCE_CXX_COMPILER. However we
rely on this macro and don't want to do what CMAKE_CXX_COMPILER
is doing. Here is what I get with CMake 3.9.1:

	CMake Deprecation Warning at /usr/share/cmake/Modules/CMakeForceCompiler.cmake:83 (message):
	  The CMAKE_FORCE_CXX_COMPILER macro is deprecated.  Instead just set
	  CMAKE_CXX_COMPILER and allow CMake to identify the compiler.
	Call Stack (most recent call first):
	  cmake/toolchains/Toolchain-arm-none-eabi.cmake:37 (cmake_force_cxx_compiler)
	  /usr/share/cmake/Modules/CMakeDetermineSystem.cmake:94 (include)
	  CMakeLists.txt:263 (project)

Avoid the warning by passing -Wno-deprecated to cmake.

* NuttX cmake

* px4_macros:Pass the stringified predicate as second arg to static assert

   CC_ASSERT mapes to the c++ static_assert or provides the same
   funtionality for c via the other macros. The c++ static assert
   takes 2 argumants the prdicate and a message. This fixes the
   lacking second argument.

* Updated nuttx and apps submodule to upstream nuttx 7.21+==master

   This is the latest uptake of upstream nuttx and apps.

* ROMFS generate with xxd instead of objcopy

* delete nuttx-patches

* NuttX update submodules to latest px4_nuttx-master

* fix nuttx apps and board dependency

* docker_run update to latest container 2017-08-29

* cmake ROMFS portable sed usage

* NuttX update submodules to latest px4_nuttx-master

   Superceeded by nxphlite-v3 before released

* Makefile target "check_stack"