shared_ptr -> std::shared_ptr

This is one of the first commits in a plan to remove all `using namespace std;` lines in the entire codebase as it is considered anti-pattern today.

Minecraft.Client/Common/XUI/XUI_SignEntry.h

@@ -43,7 +43,7 @@ public:
 	XUI_IMPLEMENT_CLASS( CScene_SignEntry, L"CScene_SignEntry", XUI_CLASS_SCENE )
 
 private:
-	shared_ptr<SignTileEntity> m_sign;
+	std::shared_ptr<SignTileEntity> m_sign;
 	D3DXVECTOR3 m_OriginalPosition;
 
 };