[TYPO3-dev] Add to CGL: Use self:: for static method calls where possible

[Sebastian Michaelsen]

Inspired by Nikolas' and Georg's RFC #13611 "Replace calls to 
t3lib_div:: within t3lib_div to self:: du to performance reasons"

I digged a bit around in t3lib and found a lot of stuff to be optimized 
(some of that is pending in the core list now). I noticed that also 
quite new Classes (e.g. t3lib_SpriteManager) include that mistakes.

The CGL be extended with:

Static Method Calls
===================
Whenever a static method is called from within the same class self:: has 
to be used instead of the class name.


Opinions?