Add findmsigaddr MGW API call.
Add findmsigaddr MGW API call.

Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2,Bitcoinsulting/multigateway-v2