Prepared version 0.6

Prepared NEWS and ChangeLog for KEDR 0.5

Updated ChangeLog and NEWS for version 0.4.1

Updated the change log and the news file for the upcoming KEDR 0.4

Cosmetic changes in NEW and ChangeLog

Prepared KEDR for the release of version 0.2.1

Bumped version in the code and in the docs, revisited/added NEWS, THANKS,
ChangeLog, etc.

doc: Minor fix in "Overview"

Removed tag v0.1