Implemented envelopes collected
Added initial saving of life time scores
Added access to collected envelope history
Added Mixpanel tracking to game properties
Added super property for skipping intro
Added super property for total new games and game overs
Added tracking to pausing game
Added tracking for reaching new highest level
Adding super property for total envelopes collected/deleted
Added how many letters short and how many letters the player had left to data collection
Made separate dev and prod Mixpanel tokens