Move happiest and unhappiest methods into Score class

Use SQL limit instead of slicing results - will be much more performant
once the data size starts growing
rename variables and methods to communicate intent better and remove outer conditional by using the suffix if
Redirect if the user doesn't exist

Fix indenting to use normal ruby 2 spaces
Start organizing lib structure better
Clean up username parameter
First pass creating a chirper class to wrap the twitter gem

It's better to not code the app against the 3rd party lib, instead we
hide it behind our own interface which will allow us to swap it out if
we need to. Plus we only need to implement enough interface for our
needs.

Additionally we also want to remove the global $client variable