Add a JS hook for has_many_remove:after
Trying the latest ransack

Trying the latest ransack to be compatible with the latest squeel.
Uses ransack 1.3

Uses ransack 1.3 to be compatible with the rails 4.1
git ignore bin folder (for rails 4 dev usage)
reimplement `ActiveAdmin::ResourceController performing batch_action` spec
implement missing spec in unit/resource_controller_spec
fix test for 1.9.x
Easier extending default show page

I would like to add few fields to show page, but keep the defaults.

Passing block to `default_main_content` would make it use defaults + block.
introduce ActiveAdmin.flash
tests for ActiveAdmin.flash
Use a select field for a boolean input
fix site title of namespaces
Use Ransack 1.3 or higher
test yielding block of default_main_content
correct usage of generator source_root
change lambda to proc
Merge pull request #3376 from timoschilling/generator_source_root

correct usage of generator source_root
Merge pull request #3365 from timoschilling/fix_namespace_site_title

fix site title of namespaces
Merge pull request #3355 from timoschilling/gitignore

git ignore bin folder, to support binstubs
Merge pull request #3358 from mikz/patch-1

Easier extending default show page