Modified behaviour of KRSprite's

KRSprite's no longer have a "sprite_size" attribute.  Instead, the node's scale is used.
KRSprite's no longer orient towards the camera automatically.  This enables applications to perform their own orientation behaviours and use the sprites for UI elements that may rotate.

--HG--
branch : nfb

KREngine/kraken_standard_assets_osx/Shaders/sprite_osx.vsh

@@ -32,11 +32,10 @@
 attribute mediump vec2	vertex_uv;
 uniform highp mat4      mvp_matrix; // mvp_matrix is the result of multiplying the model, view, and projection matrices
 uniform mediump vec4    viewport;
-uniform mediump float   flare_size;
 
 varying mediump vec2 texCoord;
 
 void main() {
     texCoord = vertex_uv;
-    gl_Position = mvp_matrix * vec4(0.0, 0.0, 0.0, 1.0) + vec4(vertex_uv.x * viewport.w / viewport.z * 2.0 - 1.0, vertex_uv.y * 2.0 - 1.0, 0.0, 0.0) * flare_size;
+    gl_Position = mvp_matrix * vec4(vertex_uv.x * 2.0 - 1.0, vertex_uv.y * 2.0 - 1.0, 0.0, 1.0);
 }