make root_path options configurable
refactor AttributesTable#content_for
refactor AttributesTable#content_for specs
add spec for settings setter
add support for `config.setting_name?`

This adds a ActiveModel like questionmark attr checker:

  inheritable_setting :foo, true
  config.foo? # => true

  inheritable_setting :foo, false
  config.foo? # => false

  inheritable_setting :foo, ""
  config.foo? # => false

  inheritable_setting :foo, "bar"
  config.foo? # => true
fix build_comment_form method
Merge pull request #3611 from alexesDev/fix_build_comment_form

fix build_comment_form method
Merge pull request #3540 from activeadmin/setting_with_questionmark

Setting with questionmark
Merge pull request #3528 from activeadmin/refector_attributes_table

Refector attributes table and his specs
add byte order mark option to csv
Merge pull request #3519 from activeadmin/csv_byte_order_mark

BOM option for CSVBuilder
Merge pull request #3502 from activeadmin/root_to_helper_name

make root_path options configurable
Adds datepicker header styling
remoed depend on asset for datepicker-header-bg.png
Finished css styling replacing datepicker-header-lg.png
Fixes braces
deleted datepicker-header-bg.png
another formatting change to try to apply styles
add &before to scss
added border to test