Implement Enumerator.new and Enumerator#each

Implementation of Yielder and Generator inspired by Rubinius
Implement Object#to_enum and Object#enum_for
Implement Enumerator#next, #next_values, #peek, #peek_values
Implement Enumerator#with_object
Remove extra line at end of lib-topaz/enumerator.rb
Clean-up whitespace and parenthesis to properly follow style-guide
Merge branch 'master' into Enumerator
Implement various "returns an enumerator if not given a block" specs

(the easy ones)
Use Fiber to implement Enumerator#{next,peek}
Merge pull request #518 from obolzer/Enumerator

Implement most of Enumerator