[TYPO3-project-4-3] improve the errorhandling

[Steffen Kamper]

Hi Rupi,

thats great, many thanks for it!

i looked over and seems to be complete.

Maybe we can add some tiny stuff:

* a table of integers showing some combination of Error constants, as 
you need to configure it with integer.

The rest is very good described, and it's the first document describing 
it, superb.

How is the state of your latest version (v6)? I was exited with version 
3 already as i used it for some days. It's a great improvement as it 
connects the methods we have in a good way. So i look forward to see a 
RFC and to get it in.

vg Steffen