Installation:
 * add another step (databaseCheck); warn if not UTF8
 * provide charset example in config.ini.sample.php
 * missing translation strings from some forms
 * handle last step ('finished') being refreshed or language selected
 * handle incomplete install (i.e., anonymous user or initial site not created)

index.php:
 * handle session.save_path not defined, unable to mkdir, or not writable

MySQLi:
 * handle connection error
 * uncaught exceptions from Dashboard, ExampleFeedburner, and LanguagesManager



git-svn-id: http://dev.piwik.org/svn/trunk@1609 59fd770c-687e-43c8-a1e3-f5a4ff64c105