update tests and maintain old behavior for backwards compatibility

decode.js

@@ -14,6 +14,7 @@ function read(buf, offset) {
   do {
     if(counter >= l) {
       read.bytes = 0
+      read.bytesRead = 0 // DEPRECATED
       return undefined
     }
     b = buf[counter++]

test.js

@@ -126,6 +126,7 @@ test('buffer too short', function (assert) {
   while(l--) {
     var val = decode(buffer.slice(0, l))
     assert.equal(val, undefined)
+    assert.equal(decode.bytes, 0)
     assert.equal(decode.bytesRead, 0)
   }
   assert.end()