remove old-style item review
add new SQL table for reviews
add a config file for reviews
add review retrieval code to item class
begin review API

Implement the API to review an item as member of the stdlib team.
do not allow re-review of reviewed items
remove unnecessary error checks

This is already done during the query, in db.php
add an other SQL error check
if the review is done, transfer the decision to the item table
fix syntax error
add missing variable
rename method so it is not mistakened as a constructor
fix SQL for adding a review
add missing step when checking for an existing review
add a review status API
Merge pull request #38 from Library-Distribution/review-api

Implement an item review API