Somewhat learning Godot's theme system... (b0.4)

A fairly pertinent thing I wanted to update regarding this tool was the use of the default Godot theme. Even if the new UI didn't look necessarily better, I wanted it to be an opportunity to start to learn how UI theming works - something I had not messed with yet, despite using Godot for quite a while now. It's not fancy, but it's something other than the default theme:

As you can see above, there's also now tabs at the top for different menus. I'll be using that as to prevent the UI from getting horribly cluttered. I can probably fit everything in one screen, but don't really see any reason why that would be a good idea.

There is also now a seek slider around the left half of the bottom of the screen, where you can adjust the current playback position of the audio, just like in any other media player. It only displays seconds at the moment, but I may change it to indicate minutes in the future. As well as dragging the seek slider back to 0, you can hold Left Shift to get the Play/Pause button to turn into a "Restart" button that will stop audio playback and restart the source.

Finally, in the Record menu, there are now three buttons for recording and saving audio. It's a very rudimentary system, and I have yet to solve any way to render audio faster than real time (currently you need to start recording and just sit there with it playing until it finishes), but I'm not sure on the details of how that would work, or rather if it's even possible with Godot. This is at least cleaner than pulling up Audacity and recording your system sounds, albeit a likely temporary solution.

Up next will be the audio effects system (which will essentially just reflect the built-in audio effects available to the engine), finding some way to render audio faster if I can, and cleaning up the modulation page to match the rest of the UI. If you have any feature suggestions, feel free to bring them up!