Added the method Configuration::Add

This methos should allow loading configuration entries as n array
instead of parsing from file.
Migrated global configuration to new loading scheme

global configuration will now be loaded by Configuration::Add
Migrated access control configuration to new scheme

Ditto as global configuration
Configuration::Add will now correctly dispatch

Callbacks waiting on categories loaded via Configuration::Add will now
be called as expected.
Migrated PHPMailer configuration to new scheme

Ditto
Removed Configuration::Load

Configuration will no longer be loaded by parsing files
Configuration no longer needs INI