freakz: Make test_app_init is the common initial function

The ravenusb caller path
    main -->
        freakz_init
        test_avr_init ---> test_app_init

So move test_app_init to the freakz_init function.
freakz: Clean the old test file
move Makefile to the common
Update os/Makefile.include to the latest contiki
Delete the unuseful file for freakz
Update Makefile.rf230 to the latest 2.7
avr: Delete CONTIKI_TARGET_DIRS_CONCAT

Since it have been deal with for the os/Makefile.include file.
So delet it.
fix compile fail