Factor out the following:
 - PKGNAME with ros- prefix. This is overrided for a few base pkgs only
 - MAINTAINER
 - LICENSE

These can still be overriden on a per pkg basis.

py-rospkg is not available from the same repositories as the rest of ros-base,
so use a standard Makefile for fetching it from github.org/ros

While here, update to 1.0.7 (changes unknown).

Instead of the mostly hidden location on pr.willowgarage.com, consistently use
github.com/ros for fetching the distfile