Fix blank screen issue
Also fix some other bugs and improvements (easier party modes, volume fixes, new fields for screens to control volume and popups)
Fix inaccessible buttons
Fix missing song length and wrong volumes (int=0-100, float=0-1)
Also fade in preview music
Fix some elements not selectable
Fix keyboard name selection
Fix warning design
Merge pull request #115 from Flamefire/develop

Develop