Revert "Added compiler conditionals for PCL 1.6 and 1.7 changes"

This reverts commit a53077c84f63dbfcd61e2000c4968f4f34c506af.

Conflicts:

	gazebo_plugins/CMakeLists.txt
	gazebo_plugins/src/gazebo_ros_depth_camera.cpp
	gazebo_plugins/src/pcl_conversions_compatibility.h
Revert "Added PCL to package.xml"

This reverts commit 6b3b0b86178df29ab569def03954fec5f813a383.
Merge branch 'hydro-devel' of github.com:ros-simulation/gazebo_ros_pkgs into hydro-pcl-conversions
Merged hydro-devel
Added back PCL dependency
Fixed template
Merge pull request #89 from ros-simulation/hydro-pcl-conversions

Add Grooby pcl_conversions