according to http://www.apache.org/legal/src-headers.html#headers, there
should be no copyright notice in the header.

- added zero-version variable in zero-framework.el

dbus based sync and async api both works.
- added error handler for dbus client in emacs lisp.
- use lexical-binding for all files
- added M-x zero-reload-all this will byte compile and reload file files.