Added file deletion after printing.

src/printer.py

@@ -171,6 +171,8 @@ class Printer(object):
             self.printer.cut()
             self.printer.close()
             self.app.logger.debug("Printed an image : " + str(path))
+            os.remove(path)
+            self.app.logger.debug("Removed image.")
             return True
         except Exception as e:
             self.printer.close()