Build: Upgrade to Grunt 0.4.5

* Switched to Grunt 0.4 API
* Upgraded to grunt-contrib-jshint 0.10.0
* Switched from grunt-wordpress to Gilded WordPress
* Reorganized most of the code
* Added .jshintrc
README: Remove (duplicative and outdated) license info
Build: Use spawnback instead of deprecated grunt.util.spawn
API Sites: Remove xmltidy task

This task was never used and produces output that we wouldn't want
to work with.
Buid: Remove superflous fields in package.json
Build: Remove dates from copyright notice
Util: Don't use Grunt internally
Tasks: Expose grunt-wodpress tasks
Tasks: Expose post preprocessor to replace old helper
Exports: Expose syntax highlighter to replace old helper
README: Document tasks and exports
Build: Update author