remove vundle, add vim-plug

vim-plug gives more control over vim plugins, allowing me to set when a plugin loads, scripts to run on install, and more.

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "vim/vim.symlink/bundle/vundle"]
-	path = vim/vim.symlink/bundle/vundle
-	url = git@github.com:gmarik/vundle.git
 [submodule ".config/base16-shell"]
 	path = .config/base16-shell
 	url = git@github.com:chriskempson/base16-shell.git