CI and common update:

-added webpage deploymnet stage
-added separate build stage which build all binaries and generate documentation
-added Emscripten build stage for merge to master only
-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

demos/utils/source/ecs_utils/math/vector.d

@@ -30,6 +30,11 @@ struct vec2
         else static assert(0, "Operator "~op~" not implemented");
     }
 
+    ivec2 opCast()
+    {
+        return ivec2(cast(int)x,cast(int)y);
+    }
+
     void opOpAssign(string op)(vec2 v)
     {
         static if (op == "+")
@@ -69,6 +74,15 @@ struct vec4
         }
         float[4] data;
     }
+
+    vec4 opBinary(string op)(float v)
+    {
+        static if (op == "+") return vec4(x + v, y + v, z + v, w + v);
+        else static if (op == "-") return vec4(x - v, y - v, z - v, w - v);
+        else static if (op == "*") return vec4(x * v, y * v, z * v, w * v);
+        else static if (op == "/") return vec4(x / v, y / v, z / v, w / v);
+        else static assert(0, "Operator "~op~" not implemented");
+    }
 }
 
 struct ivec2
@@ -82,6 +96,11 @@ struct ivec2
         }
         int[2] data;
     }
+
+    vec2 opCast()
+    {
+        return vec2(x,y);
+    }
 }
 
 struct ivec4