Release v3.2.2 (for Sigma v3.2.x and Ergo 3.2.x)

• Add support for multi ProveDHTuple and ProveDLog (#50)
• FlowCard blog post (#53)
• Upgrade to ergo-wallet v3.2.3 (#54)
• Add support for data-inputs to TxBuilder (#56)

Contributors:
@scalahub @greenhat @robkorn @aslesarenko

Release v3.2.1 (for Sigma v3.2.x and Ergo 3.2.x)

• Commands framework API added (moved from ergo-tool)
• DHTuple proving support
• smoke testing using MockData
• CliApplication abstract class for simplified implementation of CLI apps
• CmdLineParser for Commands
• ConsoleTesting helpers for CLI commands tests
• Scala cross compilation for 2.11, 2.12
• Extract GroupElement from Address (when P2PK address)
• AppkitProvingInterpreter implemented
• ErgoTreeTemplate operations implemented
• SecretString class to represent erasable strings