Make exit code 1 if error happens when running npm tests via powershell script

This fix make it easier on CI to fail a windows build when error happens

Author: Zhen Li

gulpfile.js

@@ -213,7 +213,7 @@ var runPowershell = function( cmd ) {
         console.log("Powershell Data: " + data);
     });
     child.stderr.on("data",function(data){
-        console.log("Powershell Errors: " + data);
+        console.error("Powershell Errors: " + data);
     });
     child.on("exit",function(){
         console.log("Powershell Script finished");

runTests.ps1

@@ -1,14 +1,15 @@
-Try
+npm install
+npm run start-neo4j
+npm test
+
+if(-Not ($?)) #failed to execute npm test
 {
-    npm install
-    npm run start-neo4j
-    npm test
+    $ErrorFound = $True
 }
-Catch [system.exception]
+
+npm run stop-neo4j
+
+if($ErrorFound -eq $True)
 {
-    "Error found while running tests"
-}
-Finally
-{
-    npm run stop-neo4j
+	exit 1
 }