revises the documentation of AR::Base.cache_timestamp_format [ci skip]
moves the new :nsec date format to the Active Support changelog [ci skip]
also rename indexes when a table or column is renamed

When a table or a column is renamed related indexes kept their name. This will lead to confusing names. This patch renames related indexes when a column or a table is renamed. Only indexes with names generated by rails will be renamed. Indexes with custom names will not be renamed.
Merge pull request #8645 from senny/rename_index_on_rename_column

also rename indexes when a table or column is renamed
unify AR changelog entries [ci skip]
Merge pull request #9344 from senny/changelog_cleanup

unify AR changelog entries [ci skip]
Skip failing test and add a FIXME note
Revert "Merge pull request #4803 from lucascaton/master"

This reverts commit bb842e8d2111e50b21a14b8bd6d89371a4b9cd68, reversing
changes made to 40c287c7983c20c498f6a8a2ea49e9a6455347f7.
This was causing issues in one of our apps we just upgraded.
ActionController::RoutingError: No route matches [GET]
"/images/favicon.ico"
favicon_link_tag now returns '/images/favicon.ico' and in 3.2 returned
'/favicon.ico'
Browsers by default look for favicon.ico in the root directory

Conflicts:
	actionpack/CHANGELOG.md
	actionpack/lib/action_view/helpers/asset_tag_helper.rb
database.yml -> config/database.yml [ci skip]
adds an example in the docs of #not with multiple conditions [ci skip]
puts a lambda around a default scope [ci skip]
removes some remaining relation bang methods documentation [ci skip]
removes relation bang methods from the AR changelog [ci skip]
Merge pull request #9345 from wangjohn/change_name_of_query_method_argument_checker_for_clarity

Renaming the check_empty_arguments method to something more descriptive.
ActiveRecord -> Active Record [ci skip]
Created an unscope method for removing relations from a chain of
relations. Specific where values can be unscoped, and the unscope method
still works when relations are merged or combined.