The correct stack size for all examples and test applications correctly.
KERNEL_CONF_STACKSIZE_MAIN is the correct stack size for any thread
using printf.
Also adapted black lists accordingly.
test_thread_msg_block_w_queue:
demonstrates the behaviour described in issue #100
and that it is solved by PR #569
test_thread_msg_block_wo_queue:
demonstrates behaviour similar to the above but without
a messge queue. This works with the current master, but
breaks with PR #569
