Add fallback to main_app's logout_path if not using Devise.
Move logout_method to application helper and add fallback to delete if Devise is no present (need a Config for this).
Merge pull request #2062 from jvortmann/fix_logout_path_and_method

Fix #1386 by removing dependency of Devise for logout_path and logout_method.
Pass symbol as an argument instead of a block
Capitalize properly all menu items, field names, etc.
Capitalize properly filter labels
fix z-index glitch
Sections::Base depend on  module
Merge pull request #2066 from dalpo/require-has-description

RailsAdmin::Config::Sections::Base should require RailsAdmin::Config::HasDescription
stop displaying field name in inline error, sum up all errors, not only base ones in flash message. This fixes no errors being displayed with nested forms or when the field with the error is not present in the form.
Refactor to fix Rubocop offenses
Merge pull request #2069 from orendon/fix-rubocop-offenses

Refactor to fix Rubocop offenses
Lower coverage threshold to 91.65 percent for mongoid
Optimize images

[ci skip]
Merge pull request #2072 from sferik/squish

Optimize images
Column#primary was removed at Rails4.2
Merge pull request #2073 from tsukasaoishi/for_rails42

Column#primary was removed at Rails4.2
Support Rails 4.2
Remove mongoid-grid_fs version lock
Use String#encode instead of Iconv

Modify to use String#encode instead of Iconv when ASCII Encodings.
There are two reasons:

1. @iconv was defined only encoding_to is NON_ASCII_ENCODINGS
2. Iconv is replaced from ruby-2.0

But when NON_ASCII_ENCODINGS, String#encoding cannot convert then
use Iconv as in the past.