end of day 1
Updated cucumber feature and test files

* Added a test for adding incorrect letter to the trash.
* Updated features file to include this scenario.
Updated hangman.rb to pass failing test

* Added method to add invalid letters to trash
* Added method to 'get_trash' that returns an array containing trashed letters
Added rspec tests for 'trash'
Updated trash to stop adding duplicates

* Added rspec tests for this functionality.
* Updated hangman.rb add_to_trash(guess) method to handle the above.
Tidied up files around erb templates
Futher tidied files