Introduced the IArticleCollector interface.
To fix ci strange error - even if CA1702 is already addressed with

the SuppressMessage attribute.
https://ci.appveyor.com/project/jwChung/articleharbor-webapidemo/build/123
Addressed that HaniRssCollector should implement the IArticleCollector

interface.
Introduced the FacebookRssCollector class.
Introduced the Actor and FacebookId properties.
Implemented the FacebookRssCollector class.
Introduced the IArticleConvertor interface.
Introduced the SubjectFromBodyConvertor class.
Implemented the SubjectFromBodyConvertor class.
Introduced the CompositeCollector class.
Renamed CompositeCollector to CompositeArticleCollector.
Introduced the Collectors property.
Implemented CompositeArticleCollector.
Merge pull request #23 from jwChung/facebook-article-collector

Facebook article collector