Remove Puppet Backend from serverspec-init menu.

Because I will remove Puppet Backend in near future.
Prototype implementation of #104
Fix for backward compatibility
Update gemspec
Fix gemspec
Merge pull request #106 from matsuo/update-gemspec

Update gemspec
Support fluent interface with chain for type explicit subject
Add specs for service type subject

Also fixed how to include modules and how to run specs.

The syntax ``:os => :xxx`` doesn't work with eplicit typed subjects.

So I separete specs into per OS and include OS helpers explicitly
Add to_s for readability of results of specs
Merge pull request #105 from mizzy/explicit-subject-type

Specify subject type explicitly
Bump up version
Add package type
Add specs for package type
Merge pull request #107 from mizzy/explicit-package-subject-type

Explicit package subject type
Add base type class
Add port type
Merge pull request #108 from mizzy/explicit-port-subject-type

Explicit port subject type
Add be_file and be_directory of file type
Add contain matcher for file type
Add specs for file type