v0.4 Addresses critiques with many small fixes and polish!

✅ Ctrl+S will now save the project.

✅ When the board is empty, only an instruction will show on how to drop image files into the program to create entries.

✅ Right click on a tier to edit it.

✅ The name of the rank will now be highlighted and focused when the rank editor pops up.

✅ The starting default directory is now set to the user home directory instead of nothing. Seemed to be using my development path and I only saw the results from one tester and their file manager was heading to the root directory of the drive. I think this was because it was still trying to reach the development directory, which wouldn't exist on their computer, but I'm not curious enough to investigate.

✅ A new 'Quit without saving the latest changes?' popup window appears when attempting to close the program while there are unsaved changes made to the project.

✅ Focus curtains will show behind popup windows when they are up and disappears when they are no longer up. The user can close it and every pop up by clicking anywhere on the curtain.

✅ There is now a notification area for notifying of successful saves (or anything else in the future) put in the rightmost area of the main toolbar.

✅ Established a global settings file to allow for remembering of future universal editor settings and for now keeps track of the last used file path.