The nodelet-core recipes are updated to 1.8.1 to be in line with
https://github.com/ros/rosdistro/blob/4551e7c32d1b34984410b79bc0ec36afe3d3d245/hydro/release.yaml.

Signed-off-by: Stefan Herbrechtsmeier <stefan@herbrechtsmeier.net>

The nodelet_topic_tools package is required by the pcl_ros package.
Common parts of nodelet and nodelet_topic_tools are put into
nodelet-core.inc.

Due to continuous URI modifications and no tests, the initial
commit of nodelet contained invalid hashes. They are corrected
with this commit.

The nodelet package.xml also lists the dependency on uuid, but the
recipe seems to work without.
It uses the SRC_URI from its ros repository (instead of the ros-gbp
repository), because in the commit
30306b6b, we agreed to use the ros
location instead of the ros-gbp location uniformly.