Z-index and event handling

higher z-index because of some absolute positionings on the site.

Sending the current colorpicker object with callback events.
This way, some settings can be done (like setcolor) from within the events
(like init)
zIndex error on overlay

For some reason, the overlay gets an z-index of 1001.
This is far more than all parents z-indexes.

So an additional check for the z-index is added.
Merge pull request #64 from hmhofman/master

Z-index and event handling