gd,refacto: added state chart addon and namespace cleanup

addons/godot_state_charts/state_is_active_guard.gd

@@ -0,0 +1,22 @@
+@tool
+@icon("state_is_active_guard.svg")
+## A guard that checks if a certain state is active.
+class_name StateIsActiveGuard
+extends Guard
+
+const DebugUtil = preload("debug_util.gd")
+
+## The state to be checked. When null this guard will return false.
+@export_node_path("StateChartState") var state: NodePath
+
+func is_satisfied(context_transition:Transition, context_state:StateChartState) -> bool:
+	## resolve the state, relative to the transition
+	var actual_state := context_transition.get_node_or_null(state)
+	
+	if actual_state == null:
+		push_warning("State ", state , " referenced in StateIsActiveGuard below ", DebugUtil.path_of(context_state), " could not be resolved. Verify that the node path is correct.")
+		return false
+	return actual_state.active
+	
+func get_supported_trigger_types() -> int:
+	return StateChart.TriggerType.STATE_CHANGE