Add logging system

[Seeloewen]

Most, if not all apps use some sort of log. Whether it be for debugging purposes or actually showing output to the user, it should be easy to understand and nice to look at. Most of my apps already use logging of some sort, but it's not really unified. Also, integrating it into a new app is often a hassle.

That's why a simple logging system will be implemented into SeeloewenLib. You will be able to display the log somewhere in your window by specifying the textbox it should use. You can also create buttons for saving/exporting the log or clearing it. Enabling and disabling the log will also be easy! Finally, to make it appealing, you will be able to choose between 3 logging types: Info, Warning and Error. Each will have its own color.