Add shape clickability.

Keep track of a per-map storage handler variable. It can be accessed if needed by adding a second parameter to the callback function.

Brown paper bag fix. I broke hyphenated mapids back in September and it took me this long to notice.

* Remove references to mousewheel.js, clean up variable.
* Add support for Continuous Zoom, enabled by default.
* Add behavior flag for disabling Continuous Zoom.
* Remove workaround from may 2007 (rev 1.1.2.15) that was causing zooming problems.

* Add style keyword to the macro layer.
* Add code to merge styles in properly.
* Allow using references to styles in lines / polys.