All C and H files now (should) feature the proper project curl source
code header, which includes basic info, a copyright statement and some
basic disclaimers.
This makes it possible to skip the call to unit_stop() in such
cases. Also use Curl_safefree() in unit test 1302 so it will
pass the memory torture test.
The UNITTEST_START and UNITTEST_STOP defines needed to do a new brace
level so that test cases can declare variables fine and still remain
fine C89 code.