documentation: update default DB config (#117), formatting, typos
specs: fix loading of minitest (#118)
tx builder: add safeguard to prevent duplicate in/outputs (#112)
builder: specs for op_return outputs (#99)
utxo store: remove @deleted_utxos and add spec to prove they aren't needed (#69)
fix migrations on mysql
Add new testnet3 seeds
refactor script parsing into class
better syncing/getblocks behaviour
cleanup handling of different modes in node/storage
port BloomFilter from python-bitcoinlib
implement SPV storage backend and network logic

The backend is based on LevelDB, and stores only block headers and transactions it has been
told to watch for. If it is used, the node will set a bloom filter on all connections,
and receive filtered MerkleBlock's, stripped of most transactions we don't need.
Can sync the chain from network or import from local data files, and notify listening
clients about received transaction outputs.
end-to-end integration tests for spv mode (WIP)