Update tooltip-delay.js

renamed to showDelay to be inline with hideDelay.
option is now an object with 'delay' and 'delayOnMove' properties for added behavior.
Default behavior is same as original.

new usage is 
showDelay:{
delay:millisecs(default:1000)
delayOnMove: true(default)/false
}

{delayOnMove: false} results in no delay as the mouse is moved along the chart.