FIX Basic functionality

After a while of not needing the application. I tried it out and saw that the basic functions of Downloading and Launching the Godot versions.

This fix makes those functions work again.

While I was at it I found a bug which loaded the local files by using the mono switch.
That bug also got fixed by adding a request everytime you use the switch while having internet. It adds 'lag' using the switch but made the fix fast and simple.

If you wanna change improve upon that, you can download the updated source code and build the app yourself.

Have fun managing your Godot versions (for real this time)!