TODO

* Right now, send_confirmation_email sends even for twitter users; it's okay since they don't have an email, but we still shouldn't send one.
* Make it easy to not use WebMock
* Clean up TODOs
* Make ClearanceTwitter::LinkedUser::TWITTER_ATTRIBUTES (set of attrs copied from profile to User upon connect) easier to change / document it
* Move the following steps up into clearance proper, from c-t and c-f:

    Then /^there should be (\d+) users? in the system$/ do |count|
      assert_equal count.to_i, User.count, User.all.inspect
    end

    Given 'there are no users' do
      User.delete_all
    end
* The generator to insert "include ClearanceTwitter::LinkedUser" into user.rb isn't smart enough; it assumes you haven't broken the clearance modules out individually, and looks for "include Clearance::User" in user.rb.