Ports /vg/'s datum component system

code/__DEFINES/components.dm

@@ -0,0 +1,16 @@
+//shorthand
+#define GET_COMPONENT_FROM(varname, path, target) var##path/##varname = ##target.GetComponent(##path)
+#define GET_COMPONENT(varname, path) GET_COMPONENT_FROM(varname, path, src)
+
+// How multiple components of the exact same type are handled in the same datum
+
+#define COMPONENT_DUPE_HIGHLANDER 0 //old component is deleted (default)
+#define COMPONENT_DUPE_ALLOWED 1    //duplicates allowed 
+#define COMPONENT_DUPE_UNIQUE 2     //new component is deleted
+
+// All signals. Format:
+// When the signal is called: (signal arguments)
+
+#define COMSIG_COMPONENT_ADDED "component_added"				//when a component is added to a datum: (datum/component)
+#define COMSIG_COMPONENT_REMOVING "component_removing"			//before a component is removed from a datum because of RemoveComponent: (datum/component)
+#define COMSIG_PARENT_QDELETED "parent_qdeleted"				//before a datum's Destroy() is called: ()