v0.6.2

This contains only a single change that was preventing a SceneGraph from being rendered on WebGL.

• Update GLSLGenerator uniform delegates to only add to the Shader.paremeters only when has its value used in the
  source. Due to some static conditions some uniforms may not be used while still being defined in the paramters list.
  When creating a ShaderProgram with WebGL, it would throw shader compilation error due to not finding in the glsl
  source. This was preventing a SceneGraph from being rendered on the Web due to the default 3D model shader.