Huge demos update

-moved C stdlib function definitions to ecs_utils.utils
-added function to calculate mix(linear interpolation) and rsqrt(fast inverse sqrt)
-added some math to vec2 (length, normalize...)
-improved renderer with possibility to use multiple materials (one per block, not perfect solution for parallel compute, but works with some requirements)
-added blending support for material (opaque, additive, mixed)
-added Android support
-added gprahical representation for mouse tools (tool_circle.d)
-added initial support for editing template components variables
-better Component and Templates listing
-added possibility to add/removes components using mouse
-move CLocation to game_core.basic and reuse in every test
-moved tools code from demos to App (now code is fully separated from demos!)
-some improvement and fixes in Snake demo, with additional systems to handle adding and removing entities
-added new demo: Particles. By now demo has several particles to spawn and support for attractors and vortexes (calculation is made as every attractor with every entity)
-fixed bug with window hover and tools
-improved tool behaviour
-added new material
-now window is always opened as maximized windowed mode
-some minor fixes and improvements

demos/external/sources/glad/gl/loader.d

@@ -35,14 +35,14 @@ bool open_gl() @nogc {
         return false;
     } else {
         version(OSX) {
-            enum const(char)*[] NAMES = [
+            enum const(char)*[4] NAMES = [
                 "../Frameworks/OpenGL.framework/OpenGL",
                 "/Library/Frameworks/OpenGL.framework/OpenGL",
                 "/System/Library/Frameworks/OpenGL.framework/OpenGL",
                 "/System/Library/Frameworks/OpenGL.framework/Versions/Current/OpenGL"
             ];
         } else {
-            enum const(char)*[] NAMES = ["libGL.so.1", "libGL.so"];
+            enum const(char)*[2] NAMES = ["libGL.so.1", "libGL.so"];
         }
 
         foreach(name; NAMES) {