Main Features

Updated the README.md file with instructions for Ubuntu 18.04, ROS Melodic Morenia and Gazebo 9 (master)
Deleted the README.md file to avoid misunderstanding in the installation procedure (dev/gazebo9 branch)
Inserted the default RotorS IMU (ADIS16448 IMU) in the list of the available sensors when running the simulation
Disabled shadows in Gazebo 9 and added the rotors_interface_plugin. The plugin is necessary for reading the sensors messages
Deleted TravisCI (.travisci.yml) file. Only one file is present in the master. The file handles all the distro.

Closed issues/pull requests

Giuseppe Silano