fix the windows bat issue.

fix the windows bat, if the goproxy doesn't work. The go build will interrupt, but the bat still go on. Add the errorlevel to catch the error.

bnd2/build.bat

@@ -4,10 +4,12 @@ set GOOS=windows
 set GOARCH=amd64
 go version
 go build -v -o electron/bnd2.exe -ldflags "-s -w -H=windowsgui"
+if "%errorlevel%" == "1" goto :errorend
 
 set GOOS=darwin
 set GOARCH=amd64
 go build -v -o electron/bnd2 -ldflags "-s -w"
+if "%errorlevel%" == "1" goto :errorend
 
 echo Building UI
 cd electron
@@ -15,3 +17,6 @@ node -v
 call npm -v
 call npm install && npm run dist
 cd ..
+
+:errorend
+echo "Error in go build"