Add example usage/getting started in readme file

[mika76]

It too me ages to figure out how this works and what it does exactly. Don't see why there isn't a small blurb on how to use it or at least a link to a proper documentation page.

[ENikS]

@mika76 If you figured out how it is done, why not share it with others?
I have very limited knowledge of web api so...

[mika76]

@ENikS it been a while and looking at my project I don't use this library - I use https://github.com/devtrends/Unity.WebAPI