Rewrite README with code examples

[chrisvxd]

Opening for discussion.

This is just a proposal based on our offline discussions regarding focussing the README on code.

If you decide to move forwards with this / something like this, still need to:

• [ ] Finish features list
• [ ] Actually test code snippets
• [ ] Figure out if it flows with other docs
• [ ] Tweak anything else ¯\(ツ)/¯

[chrisvxd]

@simon360 I've addressed all comments in your PR and tweaked it a bit. Please make sure you check over the todo list before merging!