remove inet_pton() from tests, use real IPv6 loopback for test
add sleep() and usleep() replacement for W32
Implement MHD_W32_random(), replace RANDOM() -> MHD_random_()
Remove PlibC wrappers and macros
Replace plibc_init() and plibc_shutdown()
Reverse OpenSSL <-> GnuTLS check
Remove PlibC from platform.h
Remove PlibC from autotools files
Remove PlibC files
Don't allow compile with unsupported Cygwin configuration
fix configure warnings under cygwin