Fixes #1: Improve README friendliness factor.

Many users were complaining that they were almost brought to tears when
they came across the format and content of the README.md file. Adding
a friendly greeting will leave users feeling loved and welcome.

* Specify Hello World text within README.md file.
Merge pull request #2 from fordprefect/i1-improve-readme-contents

Fixes #1: Improve README friendliness factor.