[ADDED] Article, Comment [UPDATED] Post

[ADDED]
Article - abstract class for posts and comments
Comment - class for comments

[UPDATED]
Post - moved 80% of the code into Article and changed to extend from Article.
[UPDATED] Post, Article, Comment

[UPDATED]
Post - Fixed mySQL issues
Article - Fixed private/protected vars issue
Comment - Rough clean up of mySQL - still needs work

[TESTS]
Updated all the phpunit tests
[UPDATE]  Comment and Post now Create, Read and Update. Delete still needs testing.