* Split off DB load monitoring logic into a LoadMonitor class hierarchy, to allow...

* Split off DB load monitoring logic into a LoadMonitor class hierarchy, to allow for plugins in this area.
* Use an associative array to initialise LoadBalancer objects
* By default, use Preprocessor_DOM if available, otherwise use Preprocessor_Hash. Preprocessor_Hash has worse performance.
* Fix parserTests.php for replicated databases. Use CREATE TABLE instead of CREATE TEMPORARY TABLE if there is more than one server configured.
* Log exceptions even in command-line mode.