Updating README

README.md

 # webots_run
 Isolated webots_run package from kaist_webots. Also _catkinized_ :)
+
+Code developed by David Butterworth.
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+
+## Usage
+This package launches Webots _within_ a ROS node, so you can run it from a launch file.
+In order to work, it requires to include the Webots' directory in the `PATH`.