Update for RS1 aka Windows 10 Anniversary Update Only!!
This may work on TH2 or earlier but it's not tested so probably best not to try.
This time round I have created 2 separate style scripts to add the start menu and task bar skinning back (SiB only) and also one that will add them both.
After you run the style scripts you can then run the Taskbar Style Hack followed by the Start Menu Style Hack, note that you will have to save and reload the style to see the new added classes for the Taskbar and start menu although you can still run the stylehacks before saving as well as test to see if they were applied, I have found when applying the start menu style hack sometimes you get a msstyles error, just undo and redo the action and it will usually work.
As usual best to do any testing in a VM until you are sure you know what you are doing, even though this type of modification to a default msstyles is relativity safe.