make native includes RIOT posix compatible
further clean up / filtering for cpu
add debug information to chardev_loop
Merge pull request #470 from LudwigOrtmann/chardev_debug

add debug information to chardev_loop
Merge pull request #468 from LudwigOrtmann/native_includes

make native includes RIOT posix compatible
fix nativenet_send documentation
Merge pull request #472 from LudwigOrtmann/nativenet_send

fix nativenet_send documentation
make buildtest output coloured
Merge pull request #474 from OlegHahm/buildtest_coloroutput

make buildtest output coloured
mute build tools (to be consistent with the rest of the build system)
build everything in the project directory
move include directives from header to C file
simplify and unify include pathes

additional:
* exporting include path in sys is mandatory for subfolders
* removed duplicate object file in linker call
correct filename
simplify include structure for boards

* do not overwrite CFLAGS in boards Makefile
simplified and unified cpu build structure
removed redundant include pathes from Makefiles
removed superfluous slash after BINDIR
further Makefile cleanup
use proper variables in board Makefiles