remove kaminari theme

ActiveAdmin use the default Kaminari theme, thats not nessary to have this theme inside of ActiveAdmin we can use it from the gem.
Renamed .css.scss imports to .scss
Merge pull request #3672 from alex88/sass-imports

Renamed .css.scss imports to .scss
Add simple documentation for PORO decorators

This adds just two small sentences introducing the possibility of PORO decorators
and links to the github issue where there is a full discussion with lots of context
and the gem by @kiote which not only is a solution but also serves as documentation
for what is required to write your own PORO decorators for ActiveAdmin.
Merge pull request #3688 from carnesmedia/document-poro-decorators

Add simple documentation for PORO decorators
fixing segmented control so that it appears correct when only a single segment is present
also fixing up tabs with the same bug
Merge pull request #3690 from ksylvest/master

Fixing Style of Dropdown and Tabs For Both First and Last Item Entries
add waffle.io badge

close #3681
Merge pull request #3653 from activeadmin/remove_kaminari_theme

remove kaminari theme
fix phantomjs/poltergeist

refs #3623
Fallback to use formtastic inputs
change filters input look up

move all filter inputs in his own namespace to support formtastic input_class_finder with fallback to default inputs.

refs #3633
closes #3678, #3696
Change config.allow_comments to config.comments
Enable comments on per-resource basis
change waffle.io badge style
Merge pull request #3697 from pranas/fix-allow-comments

Fixes for config.allow_comments
list search method conflicts in gotchas docs

[skip ci]