Add support for touch gestures: swipe & pinch-to-zoom.
Add support for touch gestures: swipe & pinch-to-zoom.

The interactions are a bit slow at the moment, but we can work on that.

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