Add file logger and fix log level output (#9)

Improve logging output

Reviewed-on: #9

src/libusbwrap/interface/IUsbDeviceFactory.hpp

@@ -9,7 +9,8 @@
 namespace libusbwrap {
 class IUsbDeviceFactory {
    public:
-    virtual std::vector<std::shared_ptr<IUsbDevice>> findAllDevices()                        = 0;
+    virtual ~IUsbDeviceFactory()                                      = default;
+    virtual std::vector<std::shared_ptr<IUsbDevice>> findAllDevices() = 0;
     virtual std::vector<std::shared_ptr<IUsbDevice>> findDevices(uint16_t vid, uint16_t pid) = 0;
 };
 }  // namespace libusbwrap