Added tap double tap support for graphs.
Added tap double tap support for graphs.

Allows to use touch for pan / zoom and simulate tap, double tap as mouse
clicks so other plugins can work as usual with a touch device.

jesjimher/emoncms,thaipowertech/emoncms,jeremypoulter/emoncms,jeremypoulter/emoncms,jesjimher/emoncms,inverse/emoncms,thaipowertech/emoncms,emoncms/emoncms,emoncms/emoncms,emoncms/emoncms,jesjimher/emoncms,chaveiro/emoncms,JFPayeur/emoncms,inverse/emoncms,chaveiro/emoncms,jeremypoulter/emoncms,chaveiro/emoncms,inverse/emoncms,JFPayeur/emoncms,emoncms/emoncms,JFPayeur/emoncms,inverse/emoncms,JFPayeur/emoncms,thaipowertech/emoncms,jeremypoulter/emoncms,emoncms/emoncms,chaveiro/emoncms,jesjimher/emoncms,thaipowertech/emoncms