add ROS params to configure depth and color

Params to configure depth mode, resolution and rate
Params to configure color compression, resolution and rate
Add specific launch file for the DS311 model as the default configuration works properly for the DS325 model
add depth image publisher

and launch file for the DS311 camera without launching rviz
add ROS param to enable point cloud downsampling

the param use_voxel_grid_filter can be used now to enable the existing downsampling filter in the code
add .gitignore file

ignoring *.user files generated by qtcreator
add depth image viewer in rviz configuration
demo launch includes the other launch file now
comments filters on launch file
Merge pull request #1 from efernandez/launch_comments

comments filters on launch file
remove unused variables
adds install rule for launch files
sets base_rgdb_camera_link
Merge pull request #3 from efernandez/link

sets base_rgdb_camera_link
Merge pull request #2 from efernandez/launch

adds install rule for launch files
Merge pull request #22 from pal-robotics/hydro_dev

add ROS params to configure depth and color
Add all recent merges on upstream