For backport to 1.14.

For backport to 1.14.

* Made the upgrader work with SQLite
* Implemented missing schema info functionality in DatabaseSqlite
* Merged the SQLite and MySQL schemas into the one file with the help of some replaceVars() hacks.
* Moved all primary key definitions to the field definition, moved all indexes to CREATE INDEX statements, for best SQLite compatibility.
* Made all autoincrement fields primary keys, as required by SQLite.
* Removed meaningless buzzword from the category table comment
* tables.sql: s/'0'/0/
* In SQLite the index names have DB scope. Renamed archive.usertext_timestamp, user_newtalk.user_id, user_newtalk.user_ip
* SQLite does not support UPDATE with LIMIT by default. Removed all instances I could find.
* Made query errors work in the installer.
* Fixed DatabaseSqlite::lastErrno(), made SQLITE_SCHEMA errors automatically reissue the query as suggested on sqlite-users. Otherwise upgrade breaks.
* Removed miscellaneous status information from getServerVersion(), that's not the place to put it