SIPackages: big picture

[VladimirKhil]

• fix all warnings
• remove all localization
• move property change notifiers to SIQuester
• move all XML serialization to aspect class and convert all simple types to records (remove custom equality operators and methods)
• auto upgrade on load; remove public Upgrade method(); remove Scenario and Type question properties
• add unit tests
• remove all deprecated stuff (custom hashes etc)
• move to separate repo