I used a few screenshots from the show for the head, mane and body, and vectors of Gilda for the paws, wings and tail. I also used a Bat-pony vector for the tufts on the ears; you can find these links in the source.
 
This is an updated version of the previous image, with the wings being colored blue, added chest fwuff, and fixed the ear lobe; as well as adjusting a few lines to clean it up.
 
Program used: Adobe Illustrator CS-6
 
Original Image Uploaded on December 27th 2016. 
Current Image Updated on January 6th 2017. 
Source has a recently updated version with shadows, but I’ve already merged this picture twice before and I don’t want to reupdate it again.