Release notes:
Stability improvements
- fix misses from earlier PR: log direct to stdout for scripts
- Bump dependencies (asio 1.22.1, etc)
- Make xdr client friendly
- Discard envelopes with unsigned txsets and do not fetch them
- minor fix: properly handle output file in WriteVerifiedCheckpointHashesWork
- Clarify bucketlist duration arithmetic, again.
- Clarified the required Rust toolchain in Win docs
- Refactor TxSetFrame
- Work around bugs in automake 1.15 on ubuntu 18.04 LTS
- rust/C++ bridge
- Fixes protocol upgrade bug in BucketManager test
New features
Breaking changes
- Move XDR files to separate subdirs for vCurr and vNext - as to reduce the risk of accidental deployment of future protocol upgrades