win_utf8_io.c: Use fputws instead of fwprintf.

Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>
stream_encoder_intrin_sse[23].c : Optimize of int32 -> uint64 conversion.

Optimizes int32 -> uint64 conversion by doing zero extension (int32 ->
uint32 -> uint64) instead of sign extension (int32 -> int64 -> uint64).

Patch-from: lvqcl <lvqcl.mail@gmail.com>
fixed_intrin_sse[23].c : Add new, simpler SSE code.

It's simpler but not faster so it is disabled by default. Maybe it
will be faster on newer CPUs though..

Patch-from: lvqcl <lvqcl.mail@gmail.com>
lpc_intrin* : Remove unused code.

Which in turn simplifies FLAC__lpc_restore_signal_16_intrin_sse2()
function.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
lpc_intrin_sse41.c : Optimize decoding 24 bit files on 32 bit platforms.

Patch-from: lvqcl <lvqcl.mail@gmail.com>