Add Log Viewer plugin

[mjangda]

Recommended by Markus Fischbacher: http://wordpress.org/extend/plugins/log-viewer/

[nickdaugherty]

Log Viewer doesn't play nice with developer (no log-viewer.php file for auto discovery), so opened discussion here http://wordpress.org/support/topic/missing-log-viewerphp-in-plugin-root?replies=1#post-4045133

[rockaut]

Changed structure. Should work now.

[Viper007Bond]

@nickdaugherty If a plugin doesn't have a PHP file that is the same filename as the folder, you can manually specify a value via the filename parameter. See the wordpress-beta-tester entry as an example.