v0.16.4

• Fix get_blockchain_synopsis
• Refactor walk_main_branch_to_num into separate method
• Default shared file size reduced
• API active_votes request
• Database API get_content function result now contains active_votes data member
• Dicsussion class active_votes gets filled in get_content_replies return
• Rolled back to invalid json_metadata load, fixed in snapshot_plugin hardfork operation evaluator.
• Fixing the work with the tag index
• Incompleted discussions requests processing fixed.
• API changes introduced. discussion_query select_tags field renamed to.
• More unicode checks implemented
• API changes introduced.
• Struct discussion_query is now equipped with filter_metadata_tags param.
• get_discussions_by_* support filter_metadata_tags selection.
• get_discussions_by_* API functions result return moved.
• Max iteration count limit removed from get_discussions function.
• Explicit filter functor return type used.
• Invalid json_metadata with snapshot-loaded accounts fixed
• Tag filtering improved.
• Category filter changes
• Category filter implemented
• Fixed new API placement
• Implemented get_steem_per_mvests and get_account_count in wallet API.