Refactored code for projectile handeling from WorldState to new class ProjectileHandler
Refactored code for tower handeling from WorldState to new class TowerHandler
Refactored code for mob event handling to WaveHandler
Refactored code for stats  handeling from WorldState to new class Stats
Minor fixes in refactoring code related to WorldState
Added delta parameter to GameObject's update method and implemented accordingly
Added spawning interval and delay to Wave
Implemented time based spawning and delay in WaveHandler
Added getters for delay, levels, total levels in wave handler
Added current level and delay time to Stats View
Fixed merge conflicts
Implemented delta in tower and restructured construct method
Implemented delta in mob
Implemented delta in projectile
Merged

mote-tracking branch 'origin/master'

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FocusClosestWay OK and testclass works fine