Preliminary GWT Export 2.0 release

For 1.5 users, I made two quick changes to the GWT Exporter to implement the first two features I mentioned last time: Zero-overhead Deferred Binding and 1.5 annotations.

Here's the change log:
* @gwt.export,@gwt.noexport,@gwt.exportClosure,@gwt.exportPackage now full fledged annotations instead of old 1.4 comment style
* Replacements are @Export, @NoExport, @ExportClosure, and @ExportPackage
* New deferred binding yields zero-overhead when exporting turned off
** By default, exports turned off, use <set-property name="export" value="yes"/> in your module to compile with them on

Build from the repository, or download the jar file at http://code.google.com/p/gwt-exporter

-Ray