Add emacs config file.

Now we can support theses features in emacs:
1. Basic setting.
2. My favorite color theme.
3. Integration git to emacs.
4. Integration sdcv to emacs.
5. Add xcscope for browser source code.
6. Update org-mode to the lastest version.
7. Set file to read only when open it.
8. Add yasnippet support.
9. Add ibus support.

Signed-off-by: Yunchao Chen <chenyc@marvell.com>