Adds Tasks for Publishing Example to Github Pages.

+ Installs [`gulp-gh-pages`](https://github.com/rowoot/gulp-gh-pages) plugin.
+ Adds task for publishing example directory to gh-pages.
+ The plugin doesn't seem to be written to copy files from multiple directories to gh-pages. Adds task for building example that copies files needed into example directory.

You can see the result here: http://jehoshua02.github.io/ddm-dropdown/