launch file updates

move launch files to test subdirectory
fix axis.launch to support current driver parameters
add .gitignore
Add camera_info_manager support to Axis driver

Adds a new dependency on the camera_info_manager_py unary stack.
Provide a generic Axis camera default_calibration.yaml.
Add new camera_info_url parameter.
Rename test/ subdirectory to tests/.

fixes #4
Merging camera_info_manager support from @jack-oquin.
Ported project to catkin.  Note that this also required me to port camera_info_manager_py to catkin