Overhaul of the mysqli interface

[julmud]

The mysqli interface (file mysqli.php) is riddled with bugs due to its old age. A complete rewrite might be a good idea.

Objectives:

• Don't mask any error message with '@'.
• Handle all potential exceptions correctly.
• Still offer the same interface to the outer world.
• Maybe use namespaces?

[gjnoonan]

Whilst we are overhauling the database side of things I think it would be be worth considering a move to PDO instead of mysqli? This would allow us to support different database drivers too with minimal effort, and without the extra baggage of a third party ORM package.

SQLite 3 support would be a perfect usecase.