Working on how to actually write the archive.

Made SuperblockFlags public so you can set options when writing

writer_write.go

@@ -0,0 +1,12 @@
+package squashfs
+
+import (
+	"errors"
+	"io"
+)
+
+//WriteTo attempts to write the archive to the given io.Writer.
+func (w *Writer) WriteTo(write io.Writer) (int64, error) {
+	//TODO
+	return 0, errors.New("I SAID DON'T")
+}