[TYPO3-ect] tx_base - tslib_pibase modernized

[Elmar Hinz]

> 
> Simply use: isDestinationCached. 
> 
> a) If you set it to true with a USER_INT: no problem but not pretty.

This would lead to unexpected caching if checkCHash is on. 

> b) If you set it to true with a USER: fine.
> c) If you set it to false with a USER_INT: fine.
> d) If you set it to false with a USER: It falls back to the default cache.
>