BHD wallet updated to v1.3.1

Updated On Aug 1, 2019

Consensus of this wallet will be upgraded in the height of 197568. For details, see Notice on the establishment of BHD Development Foundation and upgrade rules for unconditional miners

Changes as for relevant RPC interface:
1. The getrawtransaction interface returns "subsidy" and "takeoff" fields in the coinbase transaction after the height up to 197568, which indicating the cumulative rewards of conditional mining and the rewards of unconditional mining that are added to the current pool;
2. The getmininginfo interface returns the current accumulated reward data and other data in the "reward" field;
3. The sendtoaddress interface supports payment to multiple addresses.