featureflags 0.2.0

Simple implementation of the 'Feature Flags' pattern as a Ruby gem. Allows you to set defaults in a Hash of the form: ```{ feature_name_1: true, feature_name_2: false, feature_with_variations: 'A' }``` and override them with correspondingly-named environment variables. In the example above, you could enable the feature 'feature_name_2' with the environment variable 'FEATURE_NAME_2'.