Invalid labels for values in ToDot

[gballet]

The labels for values are invalid (i.e. odd length). It should be a hex number of length 2. For example:

> go test . -v -run StatelessToDot
=== RUN   TestStatelessToDot
    stateless_test.go:260: digraph D {
        internal [label="I: eb67f6353c1f453a9512383eeb34945f40206d8fe3ed42bebdc6c29fc9ce2e0e"]
        internal00 [label="I: ab2e479b08668da85552deceda89f4d146d166df1edf747d27fc8c17e72b8e17"]
         internal -> internal00
        internal0000 [label="I: b02fa3b63cf0c7fce3285289addb37ae85a2349849427e32991737bb0efc1812"]
         internal00 -> internal0000
        leaf000000 [label="L: 0e559cdbf69ad33c717d55e2bc614a168b8cf4cbd157e9e2ced34780d56a64ac
        C: 6fc5829749c78b282c12be87cd0d2bf93643a86c6a04b6944e776ce2e1869e2b
        C₁: 6248ff54938c5012552431f37b9c3b25f6e0c21e3693cf09cebfe6786922e7b0
        C₂:0000000000000000000000000000000000000000000000000000000000000000"]
        internal0000 -> leaf000000
        val0000000 [label="4000000000000000000000000000000000000000000000000000000000000000"]
        leaf000000 -> val0000000
        val0000001 [label="4000000000000000000000000000000000000000000000000000000000000000"]
        leaf000000 -> val0000001
        
        leaf000010 [label="L: 1969409cd73c960d78cfb6f85764d0c419a065118622d25a7972e35082a10d60
        C: 4b15d23dce43e8d9700d6780ae1dc15afcf7aa1be14b80bb2125e8928c7ebe5c
        C₁: 63ba41c5a741c3978836b6a35db96872e1b43ece69a9ae0c744defa77fea26d0
        C₂:0000000000000000000000000000000000000000000000000000000000000000"]
        internal0000 -> leaf000010
        val0000100 [label="4000000000000000000000000000000000000000000000000000000000000000"]
        leaf000010 -> val0000100
        
        
        
        }

val0000100 should be val00001000 since it is a hex number. The last value 0, isn't represented by a 2 digit hex number, but only by 1.