Proper initialization of arrays

The previous modification did not correctly initialize them.
Merge pull request #75 from lorenzoriano/fix-nodehandle-constructor

Fix nodehandle constructor. Thanks for the catch Lorenzo. Those were 2 stupid mistakes. I've merged, and will do a new debs release pretty soon when I've fixed a reported bug.
Merge pull request #3 from ros-drivers/hydro-devel

Merging corrections