Update gemspec
Add entities
Move entities to /quotes folder
Add spec_helper
Add excerpt entity
Add entities
Add Services
Extract assertion_helpers; refactor excerpt_spec
Add support folder to /lib
Add kindle_importer
Add nokogiri gem
Refactor validation_helpers
Remove unused 'let'
Refactor kindle_importer
Add 'tags' to excerpt
Add sample_wordpress_blog
Add wordpress_importer
Refactor wordpress_importer
Remove whitespace
Add use_cases to manifest file