Version 0.4.1

What's new:

• Creating Merkle tree and proofs of its elements:

List<byte[]> leafs = asList("one".getBytes(), "two".getBytes(), "three".getBytes());
MerkleTree tree = new MerkleTree(leafs);
byte[] rootHash = tree.rootHash();
byte[] proof = tree.proofByLeaf("two".getBytes()).get();

Then you can use these root hash and proof in checkMerkleProof() function in smart contracts.