ART: added world and level selection screen, progression art
GAMEPLAY: added playground structures:
Tower
- allows to move to other towers and playground structures
Stairs
- a one-way entry to the playground structure
- slows the dream down when on the stairs
Bridge
- connects two towers
- can be built on top of empty space, allowing to bridge the gaps
Slide
- one-way exit point for the playground structures
- stuns the dream on exit for 2s
GAMEPLAY: level structures are now sorted by world in the editor and level selection screen
GAMEPLAY: R hotkey is now used to rotate structures
GAMEPLAY: fast dreams will now swap with slow dreams in front of them