[Perception] Targe tree detection

[tongtybj]

@chibi314 motion にmerge してみてください。　エラーがあったら教えてください。問題がなければこっちをまずmergeすると思います。

[tongtybj]

@KahnShi @chibi314 A simple tree detection based on color filter and 2D laser clustering. You can try with gazebo:

$  roslaunch jsk_uav_forest_simulation forest_simulation.launch manual:=true gui:=false
$  roslaunch jsk_uav_forest_perception tree_detector.launch simulation:=true

Start tracking the target tree with following command:

$ rosservice call /sub_control true