Assertions are not runned in the child processes created with cut_fork

For example, I would expect this code snippet to fail:

``` C
#include <cutter.h>

// This will pass.
void test_proveUnexpectedFailure()
{
    int pid = cut_fork();
    if (0 == pid) {
        cut_assert_equal_int(0, 1);  // If it passes, then something is wrong...
    }

    cut_assert_equal_int(0, 0); 
}
```

But it succeeds. 
