Make sure people use nodejs for ExecJS

On OS X screen.css does not render using JavascriptCore as the backend.
In general it's the best strategy to have developers using the same
setup as in production.
Merge pull request #26 from experq/execjs_nodejs_check

Make sure people use nodejs for ExecJS
capybara-webkit 0.14 and capybara 2.0

Upgrade to latest versions so that we can make use of the latest apis.
The biggest change is that capybara 2.0 does not allow find to match
multiple dom items so our queries need to be crafted so that only a
single match is found.
Merge pull request #27 from experq/test_framework_update

capybara-webkit 0.14 and capybara 2.0
Fix modal dialogs on small screens

On small laptop screens the relative positioning of the modal dialogs
could push the larger dialogs out of the screen without showing
scrollbars. This commits makes the body to be always 800 pixels tall. I
tried basing this over the tallest dialog I could locate but due to
unfamiliarity with the application can't be 100% I got it right.
However, when a larger size is needed it's easy to increase the pixel
count.

I tried testing the commit with capybara-webkit but the resize_window
functionality seems to have an open issue in their tracker about not
working properly.
Merge pull request #28 from experq/small_screen_fix

Fix modal dialogs on small screens
ExecJS was missing from the Gemfile
Oops, forgot the .lock
Security update rails_admin

rails_admin says that versions until 0.4.3 are vulnerable to the YAML
parsing problem that was also a problem for Rails. This is only a
problem for serialized fields and hhj does not use them so we shouldn't
be currently vulnerable. I only realized that after upgrading but it's
still good practise to keep things updated.

I had troubles loading old sessions so the commit just changes the
secret token so that old sessions get discarded. To get the upgrade play
together with other gems they needed upgrades (like mongoid) which had
ripple effects.
Contact person or people shown the sidebar
Alliance linked to PositionApplication
Index listing and creation for alliances
Alliances in the main navigation
Latest version of Uniform.js

Fixes prop('checked', true) not working.
Validation for checking that all applications belong to the selected call
Integration test for alliance creation
letter_opener gem
Gritter gem for adding notifications in the UI
Seed.rb updated to match reality
Alliance confirmation and email