Make the error message better for fixture errors

The stack trace has no details about which fixture is the actual problem.
Merge pull request #3985 from dogmatic69/patch-3

Make the error message better for fixture errors
Make SMTP auth reply code checks work properly.
Add some more exception message checks
When specifying Session as a component and using Session flash messages, you end up with 'Paginator, Session, Session' which doesn't make sense. Added an array_unique to remove any duplicated components.
Merge pull request #4008 from davidyell/patch-3

Update ControllerTask.php
Added *.mo and .idea to .gitignore
Merge pull request #4016 from ravage84/patch-1

Added *.mo and .idea to .gitignore
Add `.` to the list of allowed characters.

This was missed when the email validation rules were relaxed in
dc34d80f6f622e883b8c7db9ef489bd514c8701f.

Fixes #4027
Update version number to 2.5.3
Added NetBeans project folder to .gitignore

Refs https://github.com/cakephp/cakephp/commit/78fb9b559ab1745a7255583231694be99cec65c5#commitcomment-7077015
Update db_acl.sql to use correct column names.

The column names added in bb15271 were incorrect.

Fixes #4052
Add indexes to db_acl.sql in skel directory.

Copy changes in app/Config/Schema into the skel directory.

Refs #4052
Fixed sending of headers when ajaxLogin is set
Added test case for CakeResponse::send() and ajaxLogin
Mocking _sendHeader instead of send()
Merge pull request #4060 from davidsteinsland/fix_ajax_login_header

Fixed sending of headers when ajaxLogin is set
Fix accidental typo in SQL file.

Fixes #4061
Merge pull request #4044 from ravage84/patch-1

Added NetBeans project folder to .gitignore
Fix: Blackholed request when POSTing to a URL with space

Eg:

Actual Posted URL:
    /admin/settings/settings/prefix/Access%20Control
$_GET value:
    /admin/settings/settings/prefix/Access_Control

Since $unsetUrl differs, the $_GET value will get copied in to
CakeRequest::$query, causing CakeRequest::here() to return:

    /admin/settings/settings/prefix/Access%20Control?%2Fadmin%2Fsettings%2Fsettings%2Fprefix%2FAccess_Control=

This confuses SecurityComponent in the following line:

    https://github.com/cakephp/cakephp/blob/f23d811ff59c50ef278e98bb75f4ec1e7e54a5b3/lib/Cake/Controller/Component/SecurityComponent.php#L514