BitShares Mekong 6.1.0 Release

[abit]

BitShares Mekong 6.1.0 release with new APIs, improvements to P2P network security, Elastic Search plugin, account history plugin and more: https://github.com/bitshares/bitshares-core/releases/tag/6.1.0

All BitShares mainnet nodes and command-line wallets are recommended to be upgraded, although not required.