Provide a call stack for deprecation warnings where needed.

It's sometimes hard to quickly find where deprecated call was performed, especially in case of migrating between Rails versions. So this is an attempt to improve the call stack part of the warning message by providing caller explicitly.
Merge pull request #8063 from nikitug/deprecation_caller_context

Provide a call stack for deprecation warnings where needed.
Fix failing tests and use new hash style in deprecation messages
Add test for code change introduced in this commit f20032f
Merge pull request #8066 from cfabianski/AddTestForSerializationMethod

Add test for code change introduced in this commit f20032f
Fix bug when Column is trying to type cast boolean values to integer.

This can occur if the user is using :integer columns to store boolean
values. Now we are handling the boolean values but it still raises if
the value can't type cast to integer and is not a boolean. See #7509.

Fixes #8067.

Conflicts:
	activerecord/CHANGELOG.md
Remove not assigned variable warning from sqlite3 adapter test
Make caller attribute in deprecation methods optional
Merge pull request #6107 from gazay/make_caller_attribute_in_deprecation_optional

Make callstack attribute optional in AS:Deprecation
include_root_in_json allows inheritance.
Merge pull request #8072 from kennyj/remove_mattr_include_root_in_json

Allow include_root_in_json to be inheritable by using the class_attribute created by Active Model serialization module.
Revert "The debugger gem isn't compatible with 1.9.3-p286 yet. Omit it for now."

This reverts commit 7b290ad13c294005db062e746f8b79c8a192e4fa.
debugger gem is now working ok with p286
Revert "Support `Mailer.deliver_foo(*args)` as a synonym for `Mailer.foo(*args).deliver`."

This reverts commit 7e0cf563639bc7508da381b1b8321c7a89be1aa8.

Conflicts:
	actionmailer/CHANGELOG.md

See discussion at
https://github.com/rails/rails/commit/7e0cf563639bc7508da381b1b8321c7a89be1aa8#commitcomment-2075489
Fix #6951. Use query cache/uncache, when using not only database.yml but also DATABASE_URL.
Merge pull request #8074 from kennyj/fix_6951

Fix #6951. Use query cache/uncache, when using not only database.yml but also DATABASE_URL.
Fix `attributes_before_type_cast` for serialised attributes.

Public method `attributes_before_type_cast` used to return internal AR structure (ActiveRecord::AttributeMethods::Serialization::Attribute), patch fixes this. Now behaves like `read_attribute_before_type_cast` and returns unserialised values.
Merge pull request #8078 from nikitug/serialized_attributes_before_type_cast

Fix `attributes_before_type_cast` for serialized attributes.
if format is unknown NullMimeTypeObject is returned

If a unknown format is passed in a request, the methods html?, xml?, json? ...etc
Nil Exception.

This patch add a class NullMimeTypeObject, that is returned when  request.format is unknown
and it responds false to the methods that ends with '?'.

It refers to #7837, not fixes because it's not considered a improvement not a bug.
Merge pull request #8084 from acapilleri/format_never_nil

if format is unknown NullMimeTypeObject is returned
Fix find_in_batches against string IDs when start option is not specified.