NSKeyValueCoding - change exception names

[Stéphane Corthésy]

Hi,

I compared how GNUStep and Apple implement NSKeyValueCoding and saw 
that GNUStep's implementation raises a NSGenericException exception in 
-[NSObject(KeyValueCoding) handleQueryWithUnboundKey:] and 
-[NSObject(KeyValueCoding) handleTakeValue:forUnboundKey:], without any 
userInfo, whereas Apple's raises (it is undocumented) a 
NSUnknownKeyException exception (no symbolic names though, I should bug 
Apple for that), with a userInfo containing keys 
NSTargetObjectUserInfoKey and NSUnknownUserInfoKey


Stéphane