fix natspec test

* registar url string retrieval chop leading zeros now
* rewrite test using test mining
* remove temporary applyTxs from xeth

common/docserver/docserver_test.go

@@ -27,7 +27,7 @@ func TestGetAuthContent(t *testing.T) {
 
 	hash = common.Hash{}
 	content, err = ds.GetAuthContent("file:///test.content", hash)
-	expected := "content hash mismatch"
+	expected := "content hash mismatch 0000000000000000000000000000000000000000000000000000000000000000 != 9c22ff5f21f0b81b113e63f7db6da94fedef11b2119b4088b89664fb9a3cb658 (exp)"
 	if err == nil {
 		t.Errorf("expected error, got nothing")
 	} else {