Remove omnibus.rb.chef since we don't need seperate dmg building settings for chef-client anymore.
Update chef-* project definitions to make use of new build_version DSL.
Pick up omnibus-software and omnibus-ruby changes for build_version DSL.
Rename omnibus.rb.example to omnibus.rb for clarity.
Merge pull request #158 from opscode/sersut/omnibus-cleanup

Project changes for the new build_version DSL.