Fix decoding when alphabet contains regex-like special chars

[JordanArmstrong]

The decode method uses String.split to find the chunks it needs to work on. This breaks if the alphabet has RegEx special characters in it.

e.g.

        Sqids sqids = Sqids.builder()
                .alphabet(".\\?")
                .build();
        List<Long> numbers = Arrays.asList(1L, 2L, 3L);
        sqids.decode(sqids.encode(numbers)), numbers);

A simple fix would be to wrap the pattern with Pattern.quote, but I took it as an opportunity to optimize the decode a bit to reduce the number of objects we need to create.

[0x3333]

Looks good to me, just a small typo.

[0x3333]

Looks good to me.