Adding yard gem to dependency list

- #16
Beginning docs work on Event class

- #16
Making Pomodori::Event#transition protected

- #16
Commenting methods

- #16
Adding YARD generated docs to the ignore file

- #16
New comments on Event base class

- #16
Adding docs for the event classes

- #16
Nothing to see here!

- #16
Documented Pomodori::Configuration

- #16
Documented Pomodori::Setup

- #16
Documented Pomodori::Notifier

- #16
Documented ::Notifier::Osx and ::Notifier::Stdout

- #16
Documented Pomodori::Notification

- #16
Added docs for monkeypatched String object

- Fixes #16