Update document reference; add docs for pointClickCallback, and clarify clickCallback.
Update document reference; add docs for pointClickCallback, and clarify
clickCallback.

timeu/dygraphs,mariolll/dygraphs,danvk/dygraphs,klausw/dygraphs,Yong-Lee/dygraphs,davidmsibley/dygraphs,timeu/dygraphs,Akiyah/dygraphs,pshevtsov/dygraphs,reinert/dygraphs,klausw/dygraphs,mcanthony/dygraphs,mcanthony/dygraphs,pshevtsov/dygraphs,socib/dygraphs,danvk/dygraphs,kbaggott/dygraphs,petechap/dygraphs,vhotspur/dygraphs,cavorite/dygraphs,vhotspur/dygraphs,grantadesign/dygraphs,grantadesign/dygraphs,jmptrader/dygraphs,witsa/dygraphs,petechap/dygraphs,jmptrader/dygraphs,cavorite/dygraphs,mantyr/dygraphs,grantadesign/dygraphs,mantyr/dygraphs,panuhorsmalahti/dygraphs,kbaggott/dygraphs,reinert/dygraphs,mariolll/dygraphs,socib/dygraphs,witsa/dygraphs,cavorite/dygraphs,petechap/dygraphs,Yong-Lee/dygraphs,reinert/dygraphs,Yong-Lee/dygraphs,mantyr/dygraphs,cavorite/dygraphs,davidmsibley/dygraphs,socib/dygraphs,pshevtsov/dygraphs,timeu/dygraphs,jmptrader/dygraphs,kbaggott/dygraphs,kbaggott/dygraphs,timeu/dygraphs,pshevtsov/dygraphs,vhotspur/dygraphs,davidmsibley/dygraphs,panuhorsmalahti/dygraphs,kbaggott/dygraphs,reinert/dygraphs,panuhorsmalahti/dygraphs,witsa/dygraphs,danvk/dygraphs,witsa/dygraphs,jmptrader/dygraphs,grantadesign/dygraphs,mariolll/dygraphs,mcanthony/dygraphs,Yong-Lee/dygraphs,klausw/dygraphs,danvk/dygraphs,Akiyah/dygraphs,mariolll/dygraphs,davidmsibley/dygraphs,witsa/dygraphs,reinert/dygraphs,mcanthony/dygraphs,mantyr/dygraphs,panuhorsmalahti/dygraphs,vhotspur/dygraphs,Akiyah/dygraphs,mariolll/dygraphs,vhotspur/dygraphs,Akiyah/dygraphs,Yong-Lee/dygraphs,Akiyah/dygraphs,timeu/dygraphs,jmptrader/dygraphs,pshevtsov/dygraphs,klausw/dygraphs,petechap/dygraphs,socib/dygraphs,davidmsibley/dygraphs,petechap/dygraphs,mantyr/dygraphs,klausw/dygraphs,danvk/dygraphs,mcanthony/dygraphs,panuhorsmalahti/dygraphs,grantadesign/dygraphs