Fix Focus spells (#250)
* Cleanup fake object creation
* Remove NSubstitute dependency
* Make GameEventMgr test friendly
* Remove fake factory
Refine the instantiation and handling of fakes a bit
Make GameEventMgr fakeable (and spyable)
Make Time(Manager) fakeable
* Fix focus spells
Add tests for focus spell bug
Add tests for event subscription bug in focus spells
Fix event spam from focus spells
Fix focus spells not immediately ending when rupted/stopped
Fix focus spells not stopping when attacked
* Cleanup RampingDamageFocus
