-changes in gitignore

-changed "absent" to "excluded" everywhere
-added Events support:
 *systems are scanned by handleEvent() function
 *generate system callers for events
 *event sending have (untested) multithreaded support
 *EventInput structure in System has input components for event

source/ecs/attributes.d

@@ -2,7 +2,7 @@ module ecs.attributes;
 
 ///Used to mark optional components for system.
 enum optional = "optional";
-///Used to mark absent components for system. Enum 'AbsentComponents' should be used instead of it.
-enum absent = "absent";
+///Used to mark components excluded from update for system. Enum 'ExcludedComponents' should be used instead of it.
+enum excluded = "excluded";
 ///Used to mark readonly components for system. "const" can be used insted.
 enum readonly = "readonly";