fixtures for testing
trait controller test
modified edit trait
show flash error
modified unlinking covariate
code restyle
moved citation into rescue block
update trait controller
modified rendering
fixed error on trait/new
modifiy @new_covariates
Exclude captcha on new user signup page when environment is either
test OR test_js.
Removed commented-out line.
Merge branch 'phenolphtalein-edit_trait-2'

This addresses Redmine issues #2351 and #2198 and the second part of issue #2245.
Adding two images needed by the jquery-ui-1.10.4.min.css stylesheet.
(These missing images were causing rspec tests using capybara-webkit
to fail.)
Restored changes to the application layout (namely, code to display
flash errors) that were lost when the edit-trait branch was merged
into master.
Merge branch 'master' into RM-1694-geometry-column
Updated Gemfile.lock and updated sites fixture to work with updated
table definition.