v0.2.8 release
This release contains following changes:
- Raise ConnectionError for more clearly what happened. (#13)
- Add TxBuilder. It improves the application code for building transactions because it allows you to build transactions without directly dealing with TxOut/TxIn/Script, etc. Check the usage in #15.
- Speed up to use libsecp256k1 with ExtPubkey#derive same as ExtKey#derive