ECS core imprevement

-Adedd function to resize array to Mallocator
-significant speed up for first time ID allocation by using resizeArray instead of makeArray
-fix: onUpdate called with zero length arrays
-call updateBlocks before updateEvents (it's more accurate behaviour)
-some minore fixes
-fixed meson.build for GDC

source/bubel/ecs/std.d

@@ -152,6 +152,50 @@ else
 
 static struct Mallocator
 {
+    static T[] resizeArray(T)(T[] array, size_t length) nothrow @nogc
+    {
+        T[] ret;
+
+        if(length > array.length)
+        {
+            ret = (cast(T*) realloc(array.ptr, T.sizeof * length))[0 .. length];
+            static if (__traits(isPOD, T))
+            {
+                __gshared immutable T init = T.init;
+
+                foreach (i; array.length .. ret.length)
+                {
+                    memcpy(&ret[i], &init, T.sizeof);
+                }
+            }
+            else
+            {
+                static import std.conv;
+
+                foreach (i; array.length .. ret.length)
+                {
+                    std.conv.emplace(&ret[i]);
+                }
+            }
+        }
+        else 
+        {
+            static if (__traits(hasMember, T, "__xdtor"))
+                foreach (i; length .. array.length)
+                {
+                    array[i].__xdtor();
+                }
+            else static if (__traits(hasMember, T, "__dtor"))
+                foreach (i; length .. array.length)
+                {
+                    array[i].__dtor();
+                }
+            ret = (cast(T*) realloc(array.ptr, T.sizeof * length))[0 .. length];
+        }
+        
+        return ret;
+    }
+
     static T[] makeArray(T)(size_t length) nothrow @nogc
     {
         T[] ret = (cast(T*) malloc(T.sizeof * length))[0 .. length];