Make automatic log flushing configurable

Only set ActionView configuration inside the on_load block

Fix routes inspection order

Testcase for GH #5114.

Add config.default_method_for_update to support PATCH

PATCH is the correct HTML verb to map to the #update action. The
semantics for PATCH allows for partial updates, whereas PUT requires a
complete replacement.

Changes:
* adds config.default_method_for_update you can set to :patch
* optionally use PATCH instead of PUT in resource routes and forms
* adds the #patch verb to routes to detect PATCH requests
* adds #patch? to Request
* changes documentation and comments to indicate support for PATCH

This change maintains complete backwards compatibility by keeping :put
as the default for config.default_method_for_update.

AS::Callbacks: deprecate rescuable option

Closes #5025 part 2

Prefer || over 'or' for boolean operations

ordered_options will work if inherited from Hash, remove OrderedHash usage

Bug: cache_key.size doesn't return length of filename but size of file

Refactored two methods to use delete with a block

suggested changes.

use Hash#delete on styelsheet_link_tag

Allow ActiveResource subclasses to inherit headers from parent

form option refactor