Add get_block_range

Implement get_block_range as an instance method for Hive::BlockApi and use this method for Hive::Stream by default instead of json-rpc batch. Allow developers to pick which method to use.

AC

• Add block_api.get_block_range to Hive::BlockApi instance
• Use block_api.get_block_range for streaming (by default)
• Use account_history_api.enum_virtual_ops for streaming virtual operations (if supported)