Added new step definition for seeing buttons

So "I should see 'Finish'" => "I should see button 'Finish'"
Changed assignment setters to normal methods

deactivation_code=(arg) becomes deactivation_code(arg)
activation_code=(arg) becomes activation_code(arg)

this is because ruby does not allow us to return anything but 'arg'
as the result of a setter method, and the result of the code setters
are needed to print error message to the user
Added rspec tests for truth-/false- iness

since we need those values in the full app
Fixed cucumber tests

setup backgrounds, new step definitions, got rid of mocks/stubs
after talking to alan

got rid of require 'cucumber/rspec/doubles' ...
Implemented app/view code