New QoL features

[Bendoair]

Here are a couple of easy to fix features, that would help the app immensely. I will get to them sooner or later, but if you could include them it would be nice.

• File extension filters for the file selects.
• App reset button, to change model and other characteristics
• Copyable past promts, maybe terminal style previous promt on up arrow press, or dedicated button.

[Onion99]

Okay, I will gradually work on optimizing these issues.