Update README.md

Spelling mistake
rtt_ros: Improving error reporting in the ros.import service.
Merge branch 'hydro-devel' of github.com:orocos/rtt_ros_integration into import-error-reporting
Moving rtt_kdl_conversions into typekits, since it only contains a typekit plugin and some lua code
Updating travis to actually check the test results
Adding rtt_tf to the main readme
Merge pull request #14 from jhu-lcsr-forks/kdl-conversions-typekits

Improving error reporting in ros.import service and moving rtt_kdl_conversions to the typekits directory
Merge pull request #18 from rsinnet/hydro-devel

Update README.md
Merge branch 'hydro-devel' of github.com:jhu-lcsr-forks/rtt_ros_integration into hydro-devel