add CONTRIBUTING.md
Move import to top of file.
Only load the object cache when requested.

Instead of loading a cache key that may not exist on every request, it
should only be loaded when required.

Fixes #3717
Fix error when generating Xml.

Fix warnings/un-escaped entities with deeply nested elements.

Fixes #3718
Merge pull request #1173 from ceeram/contribute

add CONTRIBUTING.md
Merge branch 'master' of git://github.com/cakephp/cakephp
Be compatible with PHPUnit installed with composer.

Doing a class_exists() check is a simple way to check for PHPUnit being
installed via an autoloader. It also keeps things compatible with
a Vendor dir installation.

Fixes #3721
Remove test case that is no longer useful.

It is impossible for the current test to ever fail in the test suite, as
PHPUnit will always be loaded.
correct coding standards
remove user plugin
Merge branch 'master' of git://github.com/cakephp/cakephp