Add alias 'E' for sudo-editing with emacsclient

Simple "sudo e" fails to open emacsclient to edit file with root previlege. Alias named 'E' is the common solution of many emacs users.

More description available at 
- http://emacs-fu.blogspot.com/2011/12/system-administration-with-emacs.html
- http://stackoverflow.com/questions/10190358/is-there-some-way-to-open-file-with-emacsclient-user-but-with-root-permission