Minor changes.

* New head comment for vimrc.
* Initial config for 'origami'.
* Simplified mode symbol for 'airline'.
* Retain buffer in memeory when it's hidden.
* Added modeline
Enabled syntax folding for vim files.

* Added modeline setting to let vimrc folded by marker instead of
  syntax.
Color Toy plugin function added.

* new file color_toy_options.vim.
    * Implemented 2 functions for loading and saving color options to a
      config file in disk.
* new file colors_win.vim.
    * Added functions to create and setting options for window to list
      color toy options detail.