Consolidates (List|Instance)Resource#resource to the Utils module
Bumps required ruby version.

Now we're using ruby 1.9 hash syntax, the gem should not report that the required ruby version starts at 1.8.7. I've put this up to 1.9.3 as it is the lowest supported version of ruby.
Removes 1.8.7 from tested versions in README.
Stops handling 1.8.7 missing RUBY_ENGINE constant.
Merging master into reduce-duplication
Merge pull request #108 from philnash/ruby-version

Bumps required ruby version to 1.9.3.
Merge pull request #107 from philnash/reduce-duplication

Consolidates (List|Instance)Resource#resource to the Utils module