Doc improvement suggestion: Simple runnable examples

[MasonProtter]

This looks really interesting! In particular, when I read this line:

ReTest is a testing framework for Julia allowing:

• Defining tests in source files, whose execution is deferred and triggered on demand.

• This is useful when one likes to have definitions of methods and corresponding tests close to each other. This is also useful for code which is not (yet) organized as a package, and where one doesn't want to maintain a separate set of files for tests.

I got quite interested, but then reading further in the docs, I fas faced with a lot of quite verbose, technical documentation and no examples (that I could find) on how to actually do this or what it'd look like.

A very simple, self contained, runnable example of defining a test next to a method near the beginning of the docs I think would be very helpful.

[rfourquet]

Thanks for the feedback! Can you have a look and review #25 ?