Development version of node-dbus

Old implementation and architecture lacked for some features, something's like creating multiple connection and registering properties. Furthermore, there is no easy-use APIs to register service/object path/interface and doesn't work on embedded system. So I have re-implemented node-dbus in development branch:

Features:
1. Support multiple connection
2. Support method, property and signal for caller and service provider
3. Easy-use Async APIs
4. Take off GLib and GContext dependency

WARNING: New version is incompatible with old version, it has totally different APIs. We may upgrade version number to 0.1 to divided into two version.