Merge pull request #3 from zck/master

Rounds 15-21, 23-27
add DC round 5 wrap-up
History. NYC Round 2 and 8
Round 28 - NYC
DC February wrap-up
executable bits off for text files
add some more shout-outs
clarify no involvement with eHarm exploit
add round 7 for DC
add round 29 for NYC
add DC round 8
add DC round 9
add DC round 10 wrap-up
add nyc rounds 30, 31.