More-explanatory README file, fixed caliper script
* I believe the caliper script was out-of-date for the newer runner logic (if I infer correctly from the tutorial video). I modified it to use the 'mvn exec:java ...' form of invocation shown in the video. It's also possible that this script is some sort of eclipse hoodoo, in which case it'd be nice to have a version of this script as well for the IDE-averse.
* Made the readme file to be markdown, which some repositories will render nicely.
* Added links to the project and license, the getting started snippet, and expanded the instructions on building and running caliper.