addition of active admin admin_user feature with failing javascript test

the feature includes a failing javascript test which can be rectified
as soon as a decision is made on which headless drivers we are using
for capybara
finished admin admin_user features including testing delete

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594

CHANGES
1. addition of gems for headles javascript testing (currently delete popups)
  - capybara-webkit
  - poltergeist
2. Implementation of admin admin_user feature
3. modify cucumber enviroment to use poltergeist (phantomjs) by default
Tidy Gemfile and remove duplicate field from admin user list view

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594

CHANGES
1. Change double quotes in Gemfile to single quotes
2. Change gemfile hash to modern style version
3. remove duplicate email field from list view of activeadmin AdminUser
moved "given I am an authenticated user" to background task
added addtional scenario testing create functionality

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
added create story that was missing identified by by cucumber only showing 1 fail
on a bug that affected 2 view
clarified comment and redfactored method creating admin_users

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
1. clarified comment about why we do not need to confirm javascript dialog box
2. refactored method that makes admin users from a table to be more concise
refactor of cucumber create directory strucutre mirroring app

pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
chore to refactor before carrying on with more features
Merge pull request #22 from PurityControl/admin_user_feature

Admin user feature
tidy up features support files and install gems to support this

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
1. Addition of headless gem so capybara-webkit can be used without
   having to call xvfb-run as part of the cucumber command
2. create an env_local.rb with our configuration and move out of the stock
   env.rb file which can get modified or overwritten if cucumber is upgraded.
3. Get delete spec for admin/admin_user.feature to work regardless of
   javascript driver being used
refactored step_definitions to mirror app directory structure

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
implement README.md giving more information on how we use cucumber

part of pivotal tracket story https://www.pivotaltracker.com/story/show/76232594
refactored wording of features to improve clarity

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
reworded from format
Then I should be on the "Admin Admin User New" page
to format
Then I should be on the "New Admin User" page for the "Admin" role
fixed typo in features README.md

part of pivotal tracker story https://www.pivotaltracker.com/story/show/76232594
fixed typo accept_confirms to dismiss_confirms for unhappy path example
Merge pull request #26 from PurityControl/feature_refactor

Feature refactor