[LTP] Test library API changes

[Cyril Hrubis]

Hi!
This time I've added functionality to handle child processes:

https://github.com/metan-ucw/ltp/blob/master/include/tst_test.h#L48

This function forks a child, runs the function and propagates the
results to the parent process via pipe.

The function is implemented at:

https://github.com/metan-ucw/ltp/blob/master/lib/tst_test.c#L129

And used in newly converted test at:

https://github.com/metan-ucw/ltp/blob/master/testcases/kernel/syscalls/creat/creat04.c

Whith this the core test library API is more or less sketched.

PS: I would appreciate any comments.

-- 
Cyril Hrubis
chrubis@suse.cz