More TODOs.
Still more TODOs.
Documented dragging issues caused by how Mac OS X handles mouse events; also determined that multiple buttons held at once only generates one mouseDragged: signal.
Documented the xxxMouseDragged: behavior in the Mac OS X source code.
Preparation for adding tracking areas to Mac OS X Areas: we need to now pass in the sysData to each control's make() function so Area can save the tracking area somewhere (this will also come in handy when I change alternate from a bool to an integer index).
Added tracking areas to Area on Mac OS X so mouse move events can work; they work now.
Added some more exposition to a comment in bleh_darwin.m regarding tracking area options.