message: Added appveyor and travis build badges
diff: @@ -18,6 +18,8 @@ so it must always be handled first.
  [![Chat on gitter](https://badges.gitter.im/gitterHQ/gitter.png)](https://gitter.im/diligent-engine)
  [![Chat on Discord](https://img.shields.io/discord/730091778081947680?logo=discord)](https://discord.gg/t7HGBK7)
  [![Codacy Badge](https://api.codacy.com/project/badge/Grade/bb1c00eacb1740d68339d3a45f4c5756)](https://www.codacy.com/manual/DiligentGraphics/DiligentCore?utm_source=github.com&amp;utm_medium=referral&amp;utm_content=DiligentGraphics/DiligentCore&amp;utm_campaign=Badge_Grade)
  +[![Appveyor Build Status](https://ci.appveyor.com/api/projects/status/github/DiligentGraphics/DiligentCore?svg=true)](https://ci.appveyor.com/project/DiligentGraphics/diligentcore)
  +[![Travis Build Status](https://travis-ci.org/DiligentGraphics/DiligentCore.svg?branch=master)](https://travis-ci.org/DiligentGraphics/DiligentCore)
  [![Lines of Code](https://tokei.rs/b1/github.com/DiligentGraphics/DiligentCore)](https://github.com/DiligentGraphics/DiligentCore)
  