[Refactoring] TriggerComponent

[pjasicek]

At this moment, only 1 trigger area is supported by a TriggerComponent and other components rely on it.

TriggerComponent should be able to hold any number of trigger areas, which should be distinguished by some Enum and TriggerObservers should register for begin/end overlap events by specifying which triggers they want to be alerted about.

[pjasicek]

Somehow implemented with with 39d0fec

Basically actor's components are now not dependant on a concrete use of TriggerComponent since any fixture can can be sensed by the TriggerComponent. TriggerObservers get additional information - which fixture triggered the event.