Add grpc-gateway for HTTP JSON API

grpc/scripts/gen.bat

@@ -18,6 +18,14 @@ for %%A in (%*) do (
     echo Generating Go code
     !exec! --go_out=plugins=grpc:!out! %pbs%
   )
+  if "%%A"=="gohttp" (
+    set plugin=protoc-gen-grpc-gateway
+    where /q !plugin! || echo Missing !plugin! && exit /b
+    set out=%gen%\go
+    if not exist !out! mkdir !out!
+    echo Generating Go HTTP code
+    !exec! --grpc-gateway_out=grpc_api_configuration=bdware/bdledger/api/grpc-gateway.yml,logtostderr=true:!out! %pbs%
+  )
   if "%%A"=="nodejs" (
     set plugin=grpc_tools_node_protoc_plugin
     where /q !plugin! || echo missing !plugin! && exit /b