MWEB-1086 Fixed PHP fatal error

When passing HTML encoded URL like `http://www.wikia.com/%D0%A1%D0%BB%D1%83%D0%B6%D0%B5%D0%B1%D0%BD%D0%B0%D1%8F` to `isValidArticleTitle`, a `Title` istance isn't being created which casued PHP fatal error in `WikiaMapsPoiController` and makes our users refresh the page since it's freezed with loading throbber.

Changes below fixes it. I also added two more test cases for similar functionality.