+ setter for field
! pass Rails.root to subprocess
+ level configuration
! fix move_to
! improve spec output
+ alternative field
+ update simulator
! adapt travis yml to level config
adapt circle ci config
! unset field after death
+ update simulation, change of sim procedure
! update simulator
! update gems
! change method type to bio_order as it used in some other mixins
+ remove prey when moving
! let prediator hunt for longer