gazebo8 8.6.0 (#442)
gazebo8 8.6.0 (#442)

* gazebo8 8.6.0

* remove old patch

* gazebo8 8.6.0 el_capitan bottle

* gazebo8 8.6.0 high_sierra bottle

* gazebo8 8.6.0 sierra bottle

osrf/homebrew-simulation,j-rivero/homebrew-simulation,scpeters/homebrew-simulation