I know there are others out there and people can do this too but I will put this here for convenience sake.
Update : Removed Test Mode Watermark
Download : http://www.mediafire.com/download/wbeg0cmak467fm0/Windows_8.1_watermark_removal.zip
-Take ownership of C:\Windows\Branding\Basebrd\en-US\basebrd.dll.mui and replace with edited basebrd.dll.mui
-Take ownership of C:\Windows\System32\en-US\shell32.dll.mui replace with edited shell32.dll.mui
-Logout and back in