* Added callback to send notices from WikiImporter and use it in ImportReporter so...

* Added callback to send notices from WikiImporter and use it in ImportReporter so that it can use the context to get messages and send them to OutputPage (also removes on usage of $wgCommandLineMode)
* Early abort on invalid title in ImportReporter::reportPage() since a notice has already been sent
* Localised message saying the title is invalid