Add header_action method for panels
Use Capybara to better test panel rendering
Add humanize_name option to CSVBuilder#column to control humanization of column name.
Add humanize_name option to CSVBuilder too and pass it to its columns.

This allows a much DRYer code if you have many column namess you don't
want to be humanized. As a bonus, any other transitive option like this
one can be added easily in the future.
Add a JS hook for has_many_remove:after
use ‘col-actions’ as default css class for index actions
this behaves like each other col
change modal dialog css for more than button
the old style keep the same, but no it works vor more than 2 buttons
Prevent active admin framework dialog styling from clobbering all jQuery UI dialogs.
Only namespace the destructive style change.

The other defaults seem like a good idea to apply globally.
Merge pull request #3169 from timoschilling/default_class_for_actions_col

use ‘col-actions’ as default css class for index actions
#3169 follow-up: selectable_column CSS class
Merge pull request #3168 from timoschilling/modal_dialog_css

change modal dialog css for more than button
changed rspec syntax `stub` to `allow`
Merge pull request #3174 from Squeegy/master

Prevent active admin from clobbering all jQuery UI dialog close buttons
add unit test for ActiveAdmin::DSL #sidebar

ref: #3178
Merge pull request #3175 from enbaglisash/patch

changed rspec syntax `stub` to `allow`
Merge pull request #2723 from shekibobo/2552-panel-header-actions

Add header_action method for panels
oops public_send to the view context!
CSV builder: properly deal with non-strings

closes #3130; fixes a regression from #3097
fix tests after 830b0958, 3fb4c514, #3130 :frowning: