Streaming Horizon endpoint support

All of the Horizon endpoints that support streaming are now accessible as Akka Streams Sources. See the sources documentation for details.

Stellar v10 support

This release completes Stellar v10 support for implemented endpoints.

• Support last_modified_ledger and last_modified_time on Offer response objects

BumpSequence support & misc

• Added BumpSequenceOperation and associated effects.
• Ability to create KeyPair from a passphrase with KeyPair.fromPassphrase
• Account endpoint now returns additional information per asset: Trust limit, buy liabilities & sell liabilities.

XDR parsing

• TransactionResponses allow lazy deserialisation of XDR payloads.
• XDR strings can be deserialised directly.

v0.1.1

Enables the ability to query Trades in Horizon, including filtering by orderbook or offer id.

v0.1.0

This is the first version that enables transaction submission. It supports ~95% of Horizon querying endpoints.