-added more documentation

-remove update() function from entity
-currently max supported components count is 64 per type

source/ecs/attributes.d

@@ -1,8 +1,21 @@
+/************************************************************************************************************************
+*This module contain attributes used to mark components.
+*Currently only two attributes are supported:
+* - optional: mark component as optional for system update
+* - readonly: mark component access as read only (used for multithreading)
+*
+*By default components are required and mutable. "const" attribute can be used insteac od readonly mark.
+*ex.
+*Struct EntitiesData
+*{
+*   Comp1[] cmp; //mutable required component
+*   @readonly @optional Comp2[] cmp2; //optional read only component
+*   @optional const (Comp3)[] cmp3; //same as cmp2
+*}
+*/
 module ecs.attributes;
 
 ///Used to mark optional components for system.
 enum optional = "optional";
-//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";