MySQL DbdSource alter field support 'after'

The ALTER FIELD for MySQL should support 'after' just like the ADD FIELD
make coredispatcher fully BC again
Merge pull request #3759 from dereuromark/master-core-dispatcher

make coredispatcher fully BC again
improving acl perfomance by adding indexes on acl tables and reorganization joins in getting acl node function
Apply patch from 'biesbjerg' to ApcEngine

This set of changes allows ApcEngine to work with APCu and newer
versions of APC.

Fixes #3749
Remove else.

By returning early we can avoid the else statement entirely.
Update isAbsolute() to recognize stream wrapper paths.

This has the benefit that the realpath() method is not applied to a
registered stream wrapper in the constructor of the Folder class.
Using the realpath() method will break the stream.

Thank "davalb" for the original patch.
Merge pull request #3773 from ADmad/2.6-folder-streamwrapper

Update isAbsolute() to recognize stream wrapper paths.
Skip autoloaders for APCIterator

We can skip autoloaders for this class as it is provided by
a C extension and will never come from userland code.
Merge branch 'master' into 2.6
improving acl perfomance
Whitelist more URL-y characters in digest parsing.

Android clients include a full URL instead of just the URI. Also handle
situations where URLencoded bytes and document fragments are used.

Refs #3779
Mark App::pluginPath as deprecated and don't use it anymore.
Merge pull request #3783 from dereuromark/master-cakeplugin-path

Mark App::pluginPath as deprecated and don't use it anymore.
Fix typo
Merge pull request #3789 from suzuki86/fix-typo

Fix typo
Fix composer app issues with cake.php
Merge pull request #3788 from dereuromark/master-composer

Fix composer app issues with cake.php
Merge pull request #3782 from cakephp/issue-3779

Whitelist more URL-y characters in digest parsing.
Merge pull request #3761 from aka-toxa/master

improving acl perfomance