Bundling of other libraries (i.e. undotree and goto-chg)

Hi, I've found myself another bloody toe. The libraries undo-tree and goto-chg are distributed with evil. While they are great and really add value to evil, it's also a mess: The undo-tree release is older than the official (0.3.0 vs. 0.3.1). If it's just convenience to provide them, then please replace those with a note or warning when the libraries are not found. Just my 2 cents, Michael