Lots of works.

1. Changed the rules of .gitignore.
    Directories except 'bundle' & 'neobundle' can be managed by git now.
    As a result the following directories is commited to git:
        'colors', 'ftplugin', 'spell', 'syntax', 'mdx_ultisnips'
2. Removed plugin pathogen.
    Plugins Vundle & Neobundle has included it.
3. Clean works on the root of .vim.
    Directories 'autoload', 'doc', 'after' current has nothing in it, so no need to keep them.
4. Let git, instead of dropbox, manage my snips.
    Removed the symbol link to 'MdxUltiSnips' directory under dropbox directory.
    Moved all my snips there into the new directory 'ultisnips' under '.vim'.
5. Suppressed the annoying message frome easytags.
    By unlock the options 'updatetime' from plugin 'YouCompleteMe'.