Removes Gemfile.lock

Gemfile.lock should not be checked in for gems. See
http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/
for more info.
Simplifies Gemfile and adds dev dependencies to gemspec
Ensures test app is created with Spree::User as user_class
Adds login button translation

This was needed so that the tests could find the login button.
Removes calls to save_and_open_page
Changes checkout click to look for a button
Cleans up spec_helper

These changes were loosely based on the spec_helper.rb file in
spree_auth_devise.
Adds authentication helpers from spree_auth_devise
Ensures the credit card and payment pass checks in all_cards_for_user
Adds travis config
Fixes 1.8.7 incompatibility in CreditCardsController
Fixes 1.8.7 incompatibilities in the views
Merge pull request #5 from mscottford/topic/fix-specs

Fix specs