+ added connectsUnit() to connectionModel, which checks if the connection leads to/from the given unit
+ added removal of attached connections to removeUnit() in scenarioModel: connections leading to/from a deleted unit will be deleted from model, too
# removeConnection() in scenarioModel now accepts only the ID of a connection as parameter (instead of the entire connection)
- removed deleteUnitFromModel() from unitModel
+ added removeUnitFromScenario() to unitController, comprising all necessary function calls for removing a unit from view and model
# merged similar but distributed unit deletion functionality from tab and modal window into removeUnitFromScenario() call; now all use the same functionality
+ added check for existence of a unit model to its click event handler: prevents errors when units are added and clicked but not named yet
+ added check for scenario name availability to newScenarioModal....: alert if entered name for new scenario is already taken
! fixed (really stupid, really) unit deletion bug (i.e. not happening): added "#" to delete unit button $-selectors
+ added TODO to loadScenario() in authorSystemController: the whole thing is stale and just won't work