[TYPO3-core] CGL and "use" statement

[Sebastian Michaelsen]

hi everyone,

introducing php namespaces in TYPO3 6.0 was a great achivement. Working 
with them for a bit now I was asking myself if the "use" statement would 
be a good thing for our code.

What it is:
===========
It creates a Shortcut for a classname to that you don't need to write 
down the full namespace path:

use TYPO3\CMS\Core\Messaging\FlashMessage;
use TYPO3\CMS\Core\Messaging\FlashMessageQueue;
FlashMessageQueue::addMessage(new FlashMessage('flash!'));

Benefits:
=========
If you have good and speaking class names, this improves readability a low

Drawbacks:
==========
If you have too generic class names which you can't understand without 
the according namespace, readability will decrease

I think we should decide on this and adopt the decision in our CGL.

I personally think that certain heavily used classes like
- GeneralUtility (former t3lib_div)
- FlashMessage and FlashMessageQueue
- BackendUtility
should be aliased with "use" if they occur a lot in a file. (e.g. 
\TYPO3\CMS\Core\Utility\GeneralUtility occurs 145x in DataHandler)