XF 2.1 Style [TH] UI.X 2 Material 2.1.7.0.0

Changelog:

• XenForo 2.1.7 compatibility

Note: This release cannot be used on XenForo 2.0, it is exclusively for XenForo 2.1 only.

Note: This update does not require a UI.X add-on update to function properly.