#270: Update rosinstall to use github repos

we migrated jsk-ros-pkg from sourceforge to github.
#270: Add README.md

Describes about how to install jsk-ros-pkg
#270: change the url of jsk.rosinstall

migrate jsk-ros-pkg from sourceforge to github.
Use github raw url
Merge pull request #273 from garaemon/fix-rosinstall-and-rosbuild-id-270

Fix rosinstall and rosbuild for github migration