Updated .gitignore and avoided a warning in VS2013

.gitignore

@@ -35,8 +35,10 @@ profile
 **/VisualStudio2012/Release
 **/VisualStudio2013/Debug
 **/VisualStudio2013/Release
+**/VisualStudio2013/x64
 **/VisualStudio2015/Debug
 **/VisualStudio2015/Release
+**/VisualStudio2015/x64
 **/Android/bin
 **/Android/libs
 **/Android/gen

extras/Introjucer/Source/Application/jucer_AutoUpdater.h

@@ -51,7 +51,7 @@ public:
     {
         const char* updateSeverHostname;
         const char* publicAPIKey;
-        const int apiVersion;
+        int apiVersion;
         const char* updatePath;
     };