adding unit test for Curl_llist_move, documenting unit-tested functions
in llist.c, changing unit-test to unittest, replacing assert calls with
abort_unless calls
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.