message: Updated readme: added diligent graphics logo
diff: -# DiligentCore
  +# DiligentCore <img src="media/diligentgraphics-logo.png" height=64 align="right" valign="middle">
  This module implements [Diligent Engine](https://github.com/DiligentGraphics/DiligentEngine)'s core functionality: Direct3D11, Direct3D12,
  OpenGL, OpenGLES, and Vulkan rendering backends as well as basic platform-specific utilities. It is self-contained and can be built by its own.
  