Created URL encoded new username preview.
URL encoded username is now displayed in span element next to the input field.
Use AssetsManager class for JS inclusion.
Replaced $wgOut->addScriptFile() with AssetsManager's class method.
Added missing semicolon.
JS variables grouping and globals clean-up.
Grouped JS variables and removed unused global $wgScriptPath.
Fixed hardcoded message.
Defined output model for userrenametool-encoded.
The output model for userrenametool-encoded message is now escaped();
Added QQQ documentation for new message.
Used up-to-date version of i18n file.
Removed unnecessary loop and changed AssetsManager method.
Merge pull request #1341 from Wikia/CE-344

Created URL encoded new username preview.