Clean up authors in KDevelop4

[David nolden]

Hi, I'm not in the list of authors yet, and looking it the list, it contains 
lots of authors who have never contributed to KDevelop4.

I think we should remove all authors except those who did a significant 
contribution to KDevelop4. To me this means, either they have done significant 
contributions during the development time of KDevelop4, or KDevelop4 contains 
a significant amount of their code(Possibly ported from KDevelop3 or 
elsewhere).

Greetings, David