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

Improve logging output

Reviewed-on: #9

src/libusbwrap/UsbDevice.hpp

@@ -29,8 +29,8 @@
 namespace libusbwrap {
 class UsbDevice : public IUsbDevice {
    public:
-    UsbDevice(libusb_context* ctx, libusb_device* dev);
-    ~UsbDevice();
+    explicit UsbDevice(libusb_context* ctx, libusb_device* dev);
+    ~UsbDevice() override;
 
     // delete copy ctor and assignment
     UsbDevice(const UsbDevice&)      = delete;