start writing release notes

add script to generate news entry
increment version number
add keyGetNamespace to kdbproposal.h

remove keyNameGetNamespace
fix wrong error keys + implement kdbGet cascading
add cascading example
fail if no errorkey

otherwise strange behaviour might occur later (trie might not be build
up correctly)
do kdbClose with null pointer

better cleaning up something, than doing nothing
seems to be safe, some unit tests used it
cascading for kdbSet
still allow empty key for kdbSet()

(undocumented feature that is in use)
return properly for cascading plugins