`omnibus` cookbook is now pulled in using Berkshelf

The `omnibus` cookbook has been refactored and lives as a properly
released cookbook (along with it's dependencies) on the community site.
update dna.json files for new attribute naming

https://github.com/opscode-cookbooks/omnibus/blob/master/attributes/default.rb
gitignore some additional build-time tmp assets
trailing whitespace and typos