add PKG_CONFIG_PATH for rosbuild environment
Merge pull request #38 from k-okada/add_rosbuild_test

add PKG_CONFIG_PATH for rosbuild environment
(.travis.yml) add rosbuild/use_deb matrix, rosbuild and use_source need rosws init to crate setup.bash
Merge pull request #39 from k-okada/add_deb_rosbuild

(.travis.yml) add rosbuild/use_deb matrix, rosbuild and use_source need ...
add Isaac to maintainer