Enchantment request: rospkg.RosPack().get_this_package_name()

[fcolecumberri]

Several functions on this library uses the package name, but it could be useful to get the package name of the running node in order to use this library without hard-coding the package name.

This enchantment could let create libs that are interdependent of the package name.

I would make a PR but I have no idea how to get the package name.