Guides to building participants and spectators

[Kanak Biscuitwala]

I started two new wiki pages with general guides to implementing new 
participants and spectator classes in different languages (borrowed heavily 
from what we learned building the Python one). Let me know if you have any 
suggestions:
https://cwiki.apache.org/confluence/display/HELIX/Building+a+Participanthttps://cwiki.apache.org/confluence/display/HELIX/Building+a+Spectator