Assign screen

• Pads: read you to load file screen.
• Pad button: change it to pad/free_play mode.
• Seq button: change it to sequence mode.
• Pad# arrows: disabled.
• BPM arrows: disabled.
• Load button: read you to load project screen.
• Rec button: disabled.
• Rec stop button: disabled.
• Vol button: read you to volume screen.
• Save button: read you to save screen.
• FX button: read you to filter screen.
• Volume slider: master volume.