Light weight SQLite-specific schema migration

THIS CODE IS EXPERIMENTAL AND SUBJECT TO CHANGE WITHOUT NOTICE
SQLite is a light weight single file SQL database that provides an excellent platform for embedded
storage of structured data. ORLite is a light weight single class Object-Relational Mapper (ORM)
system specifically designed for (and limited to only) work with SQLite. ORLite::Migrate is a light
weight single class Database Schema Migration enhancement for ORLite.