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