Clean up a few things, move gist-vim to submodule

.vim/plugin/gist.vim

@@ -1,23 +0,0 @@
-"=============================================================================
-" File: gist.vim
-" Author: Yasuhiro Matsumoto <mattn.jp@gmail.com>
-" WebPage: http://github.com/mattn/gist-vim
-" License: BSD
-" GetLatestVimScripts: 2423 1 :AutoInstall: gist.vim
-" script type: plugin
-
-if &cp || (exists('g:loaded_gist_vim') && g:loaded_gist_vim)
-  finish
-endif
-let g:loaded_gist_vim = 1
-
-function! s:CompleteArgs(arg_lead,cmdline,cursor_pos)
-    return ["-p", "-P", "-a", "-m", "-e", "-s", "-d", "+1", "-1", "-f", "-c", "-l", "-la", "-ls",
-                \ "--listall", "--liststar", "--list", "--multibuffer", "--private", "--public", "--anonymous", "--description", "--clipboard",
-                \ "--rawurl", "--delete", "--edit", "--star", "--unstar", "--fork"
-                \ ]
-endfunction
-
-command! -nargs=? -range=% -complete=customlist,s:CompleteArgs Gist :call gist#Gist(<count>, <line1>, <line2>, <f-args>)
-
-" vim:set et: