[TYPO3-core] RFC: #11271: Use 2 level cache for BEgetRootLine

[Steffen Kamper]

Hi,

this is a SVN patch request.

Type: Bugfix

Bugtracker references:
http://bugs.typo3.org/view.php?id=11271

Branches: Trunk

Problem:
Now there is only a first level cache for BEgetRootLine, which is stored 
in a global var.

Solution:
The patch
* use a static var for first level cache
* stores second level cache in cache_hash

The patch is simular to the xml2array method, thanks Fabricio for the 
inspiration.

vg Steffen