Common update:

-added multiple new function to allocate template and add entity
-updated README.md (complete initial version)
-empty components now don't take memory
-fixedd small bug with TestRunner
-added many new tests (HashMap, Vector, EntityMeta, ...)
-added default hashing function to HashMap
-fixed critical bug with adding entities
-fixed small bug with adding entity with remplacement components
-added asserts into code to better bug detection
-small performance improvement for events
-added ComponentRef structure which contain data pointer and componentID
-remove EntityID from Event structure
-now events are handled before removing entiteis
-fixed GDC compilation
-fixed rendering of rotated sprites
-added weapons as separate entities to space ship and others
-added Tower enemy to SpaceInvaders demo
-added Boss to SpaceInvaders demo (boss has four tower attached to it)
-Boss towers shoot multiple bullets upon death
-fixed critical bug with demos switching
-fixed critical bug related to adding/removing entities form inside onAdd/onRemove entity callback
-added animation support
-added particles sypport and particles for firing and explostions, and more
-multithreaded rendering now has same rendering order as singlethreaded
-application automaticallu detect host CPU threads count
-added upgrades to SPaceInvaders demo
-fixed texture memory freeing
-improved documentation
-improved multithreaded performance
-improve shader code
-fixed registration issue
-some additional performance improvements
-added depth and colors to rendering parameters
-jobs now has names corresponding to their systems
-change execute() -> willExecute()
-added EntityMeta structure to speedup getting fetching components form entity
-improved multithreading rendering
-added possibility tio change number of threads runtime
-added bullets collision detection in SpaceInvaders demo
-some CI changes
-added VBO batch rendering (current default, no render mode switch yet)
-fixed camera positioning calculation
-fixed buffer issue with WebGL
-added viewport scalling (at least 300 pixels height). Pixels are scalled if screen is bigger.
-center demos gameplay area
-added fullpage html template for Emscripten build
-added many new sprites to atlas
-fixed critical bug with CPU usage in multithreaded mode
-snake render tile coresponding to body part
-snake is destroyed after collision and emit some particles
-added some functionality to vectors
-fixed documentation issue in Manager.d
-more minor code changes and cleanup

source/ecs/entity.d

@@ -1,76 +0,0 @@
-/************************************************************************************************************************
-Entity module.
-
-Copyright: Copyright © 2018-2019, Dawid Masiukiewicz, Michał Masiukiewicz
-License: BSD 3-clause, see LICENSE file in project root folder.
-*/
-module ecs.entity;
-
-import ecs.system;
-import ecs.manager;
-
-/************************************************************************************************************************
-Entity ID structure. Used as reference to Entity. Pointer to entity should be ever used to store entity reference!
-*/
-struct EntityID
-{
-    ///Index to entity in IDManager.
-    uint id;
-    ///Counter required for reusing ID.
-    uint counter;
-}
-
-/************************************************************************************************************************
-Structure of Entity. It's have only ID, but have full konwlege to get to components memory (If pointer to it is proper).
-*/
-struct Entity
-{
-    ///Entity ID.
-    EntityID id;
-
-    /************************************************************************************************************************
-    Get specified component. If component doesn't exist function retun null. Pointer is valid only before next "commit()", "begin()" or "end()"
-    function is called. Returned pointer shouldn't be used to store reference to entity data.
-    */
-    T* getComponent(T)() const
-    {
-        EntityManager.EntitiesBlock* block = gEM.getMetaData(&this);
-        EntityManager.EntityInfo* info = block.type_info;
-        if (T.component_id >= info.deltas.length || info.deltas[T.component_id] == 0)
-            return null;
-       
-        static if (EntityID.sizeof == 8)
-            uint ind = cast(uint)((cast(void*)&this - block.dataBegin()) >> 3);
-        else
-            uint ind = cast(uint)((cast(void*)&this - block.dataBegin()) / EntityID.sizeof());
-        return cast(T*)(cast(void*)block + info.deltas[T.component_id] + ind * T.sizeof);
-    }
-}
-
-/************************************************************************************************************************
-Entity template structure.
-
-Entity contain whole information needed to create new entity. Allocating EntityTemplate is considered as more expensive operation
-than adding entity. Whole components memory is stored in EntityTemplate and is copyied to newly added entity.
-If you want to place several entity with small difference in data then you should take pointer to component and change it before every 
-entity addition.
-
-There is no restriction about number of allocated templates. Single template can be used from multiple threads, but if you
-want to changes some components data before add entity (entity position for example) it's better to use multiple templates.
-*/
-export struct EntityTemplate
-{
-    ///Entity components data
-    ubyte[] entity_data;
-    ///Pointer to entity type info.
-    EntityManager.EntityInfo* info;
-
-    /************************************************************************************************************************
-    Get specified component. If component doesn't exist function return null. Returned pointer is valid during EntityTemplate lifetime.
-    */
-    T* getComponent(T)() nothrow @nogc
-    {
-        if(T.component_id >= info.tmpl_deltas.length || info.tmpl_deltas[T.component_id] == ushort.max)return null;
-        return cast(T*)(entity_data.ptr + info.tmpl_deltas[T.component_id]);
-    }
-}