[u104][vim] 1. <s-tab> not working; use <leader><tab> instead> 2. removing <c-[> in VimEnter.

1. <s-tab> just do not work. use <leader><tab> instead.
   <leader><tab> go to previous tab.
   <leader><leader><tab> go to last focused tab.
2. Not found ghost insert mode on u104. Remove it locally.
[freebsd91p7][vim] 1. removing <c-[> in VimEnter. 2. no locking CoVim commit ID.

The reason:
1. Not found ghost insertion method on this machine/terminal. Remove it
locally.
2. CoVim fixed loading twisted plugin issue.
Merge remote-tracking branch 'origin/u104' into freebsd91p7
[u104][vim] Use <leader><fx> instead of <c-fx>. <c-fx> not works on u104.
[freebsd91p7][vim] 1. store bookmarks under $VIM_SESSION. 2. Improves vim-bookmarks and tasklist.vim.
[freebsd91p7][vim] Use my vim-vookmark plugin as default bookmark managemnet.
[freebsd91p7][vim] 1. scripts to add vbar on statusline. 2. new plugin MatchTag.

Also add .homepage in .gitignore.