Add phpdoc comments

Merge pull request #3 from na2axl/adding_class_map

Add FETCH_CLASS mode for class mapping

Add build status on README.md

Merge pull request #2 from na2axl/implementing_link

link system added

Improve the main JSONDB class

* Use the class PreparedQueryStatement for prepared queries.
* Move methods used for prepared queries in class
PreparedQueryStatement.
* Create a .htaccess file in each created servers with user's
credentials.
* Fix bug with server's creation (server's path and user's credentials
wasn't saved)

Update composer.json