Installation instructions for using PlatformIO

• What is PlatformIO?
• PlatformIO IDE
• PlatformIO Core (command line tool)
• Advanced usage -
  custom settings, uploading to SPIFFS, Over-the-Air (OTA), staging version
• Integration with Cloud and Standalone IDEs -
  Cloud9, Codeanywhere, Eclipse Che (Codenvy), Atom, CLion, Eclipse, Emacs, NetBeans, Qt Creator, Sublime Text, VIM, Visual Studio, and VSCode
• Project Examples