Semux v1.4.0

This release includes incremental improvements and bugfixes since last version. Major changes
are the block rewards adjustment and virtual machine implementation (in place but not activated).

Bug fixes:

• Fix the 2/3 BFT quorum size rounding error (#134, #142)
• Start syncing when the number of connections is low (#130)

New features:

• Consensus
  • Update the block reward function (#151)
• VM
  • Introduce the VM fork signal (#67, #137, #139)
  • Refactor transaction results (#77, #149)
  • VM tests (#90, #97, #113, #114, #117, #112, #129, #140)
• Wallet
  • HD wallet tests (#133, #132, #138)
• API
  • Bump version to v2.2.0
  • Remove blockNumber from *TransactionType
  • Add /transaction-result endpoint for transaction result
• P2P
  • Upgrade protocol to support light client (#146)

Enhancements:

• Fast block validation using batch validation (#150)
• Add aarch64 native support (#89, #117)
• Suggest use OpenJDK (#131)
• Update error messages and descriptions (#81, #79, #94, #103)
• Add empty password shortcut (#108)
• Update dependent libraries (#79, #141)
• Limit the number of validators on testnet (#123)