Married HD wallets: Bloom filter adjustments

Bloom filter for married keychains will contain serialized redeem script and it's hash for each set of married keys.
[Previous version](https://github.com/troggy/bitcoinj/blob/master/core/src/test/java/com/google/bitcoin/wallet/KeyChainGroupTest.java#L392) of this test started failing after this change, because it asked internal chains for keys directly which breaks path synchronization of followed/following chains. That's one of the problems that still need to be addressed: as per proposed design followed and following chains have to be in sync (have same number of leaf keys derived), but followed chain is exposed through `getActiveKeyChain` and thus could possibly have more keys issued. Perhaps, `getActiveKeyChain` should throw Exception for married chains.
I rewrote the test, but encounter another problem — `currentAddress` yielding different address after serialization roundtrip (there was similar issue with `currentKey`). I'm going to fix that