Sample.rb include_recipe fix

Version 0.1.4.
Fixed bad include_recipe line in sample_recipes/sample.rb file.

Readme link fix

Version 0.1.3.
Fixes link to sample.rb file in README.md.

Improved Feature Validation

Version 0.1.2
Improves validation in the manage_feature LWRP that the requested addition or removal is for a feature that exists on the target node. It makes use of the is_feature_available?() method in the mixlibrary-core gem, Mixlibrary::Core::Windows::Features class.

First Release

Version 0.1.1
First release of window_feature cookbook.