ignore codekit configuration
memory leak fix: do not directly assign handlers to dom elements

This was some hard work (took me almost a day and learned a freaking lot about memory profiling):
- the mouse handler functions point to a closure that contains a reference to our svg-node
- if we attach the handler functions to the dom svg element directly, we create a circular reference of dom-element and memory-object, thus preventing the garbage collector of freeing up our memory resources
- attaching the handler via eventListeners resolves the problem (and removes the need for noopFunc)
add comment about event handlers for IE < 9
Merge pull request #5 from tikiatua/refactor

Fixed the memory leak