* Fixed getLatest() check in Article

* Fixed getLatest() check in Article
* Added Title::loadFromRow() function and made WikiPage::loadPageData() use it; avoids raw Title field accessing
* Added Revision::newFromPageId() function and changed WikiPage::loadLastEdit() to use it. This makes it try a slave first instead of always hitting the master. It also makes it more consistent with getLatest() for sanity.
* Made WikiPage::loadPageData() use accessor for Title::mRestrictionsExpiry