/** \mainpage Gazebo API Reference This documentation provides useful information about the Gazebo API. The code reference is divided into the groups below. Should you find problems with this documentation - typos, unclear phrases, or insufficient detail - please create a new bitbucket issue. Include sufficient detail to quickly locate the problematic documentation, and set the issue's fields accordingly: Assignee - blank; Kind - bug; Priority - minor; Component - documentation; Version - blank.

Classes
  List - Index of all classes in Gazebo, organized alphabetically
  Hierarchy - Index of classes, organized hierachically according to their inheritance

Modules
  Common: Classes and files used ubiquitously across Gazebo
  Events: For creating and destroying Gazebo events
  GUI: A set of GUI related classes, functions, and definitions.
  Math: A set of classes that encapsulate math related properties and functions.
  Messages: All messages and helper functions.
  Physics: Classes for physics and dynamics
  Rendering: A set of rendering related classes, functions, and definitions.
  Sensors: A set of sensor classes, functions, and definitions.
  Transport: Handles transportation of messages.

Links
  Website: The main gazebo website, which contains news, downloads, and contact information.
  Wiki: A collection of user supported documentation.
  Tutorials: Tutorials that describe how to use Gazebo and implement your own simulations.
  Download: How to download and install Gazebo

*/