* Allow $wgDiff3=false

* Allow $wgDiff3=false
* Don't call quickUserCan('edit') unless section edit is enabled
* In DatabasePostgres and DatabaseSqlite: throw an exception on connection error
* In DatabasePostgres: don't send an invalid connection string whenever one of the fields is empty. Use quoting.
* In Database: make the captured PHP error prettier
* Display a descriptive error message when the user navigates to index.php with PHP 4, not a parse error. Check to see if the *.php5 extension works, using file_get_contents().
* The default port number for PostgreSQL is 5432, not blank.
* Better default for $wgDBname