Making the jekyll cookbook more open

[kkenny]

1. Add cookbook name to metadata to satisfy warnings
2. Add default jekyll command to attributes
3. Rework the logic around jekyll options to satisfy warnings from chef
4. remove the join of '--' in front of the option since some options don't have the '--' prefix
5. Add a toggle switch for installing/configuring apache2 to make it more open to other configurations, such as serving jekyll up from the built-in web server
6. Tested on CentOS 7