A Load Of Fixes

There's quite a lot here:

I've applied PSR-2 standards everywhere (there were a few lapses particularly in the spec folder - some functions contained the visibility flag, while others didn't - all should be `public function ...`).

I've applied the docblock fixes as discussed on the flysystem repo (I haven't got around to looking at the flysystem repo yet - it's considerably larger than this one).

I've removed a few unused use statements.

I've also cleaned up the EmitterTrait and added a few missing functions (I don't know if you intentionally didn't put those functions in).