pass evt into contentMouseDown and contentMouseUp event
Merge branch 'pass-evt-arg'
Don't use cached event listener length in node._fire because changing shape attribures in a event could remove kinetic event handler from the array which willl cause 'hander of undefined' error.
remove unused variable.
Merge pull request #626 from kzhdev/fix-node-_fire-error

Don't use cached event listener length in node._fire because changing shape attribute could remove kinetic event handler from the array which will cause 'hander of undefined' error