Better exception models

[g105b]

Rather than throwing the uncaught PDOException, make a better model which relates to the actual problem in the SQL.

We already have QueryCollectionNotFoundException and QueryNotFoundException, when dealing with the actual filesystem, but it would be better to have the PDOExceptions wrapped in a more readable manner.

[g105b]

An example of one exception that still needs to be improved:

PHP Fatal error: Uncaught PDOException: SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens in /path/to/script.php

What variables are in the script? What variables have been given? Why not tell the developer which ones are missing?