OSIRIS for desktop, Early feedback

Thanks for the early feedback y'all. I've implemented some changes, fixes, tweaks, overall improvements. It feels a little more complete. Still a lot of work left though.

v03 changes:

• slower rock speed for more fun, fewer surprises 
• rocks now fly in from the sides instead of just above
• consistent feather speed
• easier to collect feathers
• tweaked collision of player, feathers, rocks
• refined prologue timing, scroll, audio fade
• added item count in HUD. clearer goal when collecting items

v03b changes:

• fixed HUD text not showing
• added new screenshots