Note that there's no code for user types and fields yet -- just the schema (actually there's a tiny bit of code in the item type manager, since we'll probably use some of the same methods for managing user types, but not much)
Templates for primary item types are currently only used by the item type manager to make creating new types easier and to prevent the removal of fields from an item type that are associated with its template item type -- the fields are all still recorded in itemTypeFields, since they might have different orders or default visibility settings from their templates
This lets us add tables to user.sql without writing migration steps for them yet still have the ability to change existing user tables and migrate data if necessary.
Also added _getDropCommands() to do a regex on the SQL file and create the DROP TABLE|INDEX steps necessary to use the DB_REBUILD flag without DROP commands in the SQL file itself, before I realized that it probably made the most sense to just delete the SQL file and storage directory. Changed _initializeSchema() to do that instead. Leaving _getDropCommands() in, in case there's ever a need for it.
This should make development much easier, as we can, for example, add 80 item types without having to write transition steps
Pretty sure this won't delete anyone's data. Might want to test that theory, though.
