unused var
better codestyle
fix vulnerable style: undefined var
Unused imports
Unnecessary newline in error msg
install nose coverage
reverting to prepending elements after recursion.

since non-generates setup.sh files may delete ROS_PACKAGE_PATH on their own
So when entering recursion, _ROS_PACKAGE_PATH_ROSINSTALL collects the items to add
when the last recursion is done, all the elements in there get prepended to the ROS-PACKAGE_PATH
Merge branch 'master' into fix_chaining