Some problems when installing RotorS package.

The github address of RotroS is 

https://github.com/ethz-asl/rotors_simulator

This is a powerful package for collective simulation of arial drones in ROS+Gazebo environment. Some problem happens when compiling it. (using "catkin build" command )

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missing dependencies and some small typos

1) geographic_msgs: sudo apt-get install ros-kinetic-geographic-msgs
2) future: pip install future
3) Could NOT find GeographicLib: 
    sudo apt-get install libgeographic-dev
    sudo apt-get install geographiclib-tools
4) ‘struct mavlink::common::msg::ODOMETRY’ has no member named ‘twist_covariance’: 
/home/liang/catkin_ws/src/mavros/mavros_extras/src/plugins/odom.cpp_line 234: ftf::covariance_urt_to_mavlink(cov_vel_map, msg.twist_covariance); - > ftf::covariance_urt_to_mavlink(cov_vel_map, msg.velocity_covariance);

After installing gazebo, the first run caused fatal errror after "wait for 1 second before trying to unpause gazebo". To solve this,  download the basic gazebo models from : https://bitbucket.org/osrf/gazebo_models/get/e6d645674e8a.zip. 
and then extract them in ~/.gazebo/models. One can also download this zip file from Baidu Cloud via the following link if the original website is too slow to access it:

链接：https://pan.baidu.com/s/1OU58RPRo7brbZ-vpPFCUVw 
提取码：962v