uses PATCH for the forms of persisted records, and routes PATCH and PUT to the update action of resources

Trying alternative implementations of the inflections
is hard because the suite is coupled with the current
one, setting ivars by hand etc. This commit relies on
initialize_dup, as long as you maintain that one you
can tweak the implementation.

The reconnect flag does not play nicely with transactions and so
it is of little use in Rails applications. Thus, albeit supported
by mysql2, it does not deserve such a prominent place in the
generated database.yml, which should be a representative config
example. Note that the flag is false by default.

Advanced users know from mysql2 docs that the flag is available.

The method verify_active_connections! was used in
the old days (up to 2.1 I think) by the dispatcher
to verify the connections, but nowadays we do that
in a different way and this method is obsolete.

correct fetching :name option in form fields

Update with new task names for building mysql and postgresql databases

Remove unused implementation of next_migration_number

Move config.autoflush_log to correct template

This accidentally ended up in the development template
instead of the production template, where it makes
most sense.

Remove unused global variable in controller filters test

Remove skip_filter block param

Remove reference to rails_legacy_mapper, which isn't compatible with 3.2...

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