encoding: big-endian u16

To reflect that big-endian is used in uvarint, ans also in upcoming msgpack.

encoding.go

@@ -3,13 +3,12 @@ package bcl
 import "github.com/mohae/uvarint"
 
 func u16ToBytes(p []byte, x uint16) {
-	p[0] = byte(x & 0xff)
-	p[1] = byte(x >> 8 & 0xff)
-
+	p[0] = byte(x >> 8 & 0xff)
+	p[1] = byte(x & 0xff)
 }
 
 func u16FromBytes(b []byte) uint16 {
-	return uint16(b[1])<<8 | uint16(b[0])
+	return uint16(b[0])<<8 | uint16(b[1])
 }
 
 func uvarintToBytes(p []byte, x uint64) int {