Installer updates to use DBAPI

Database calls chanelled trhough manager/includes/extenders/ database
class;
Typo fixed in action.connection.php
Default for @installset made array() instead of false in setup.info.php
DBAPI updates for use with installer

Allow for connection without database name
Remove pointless check for mysql_real_escape_string (if it ain't there,
you ain't running PHP5 or even 4.1), and deprecated reference to
mysql_escape_string()
add option for text mysql error
add no-exit test for database connection & selection