Direct to app developer resources

This is a follow-up from a UDS session [1].

It would be great if hello-unity would point to support resources and communication channels for app developers, so that app authors exploring the app would know where to go if they want to take their app development journey further and they need help.

An option might be to just add buttons or links to these resources to the about dialog, but perhaps a nicer way might be to implement it similarly as the Ubuntu One client does: a sort of toolbar that is always present at the bottom of the app and that provides a link to support and social channels. For hello-unity, it could be:

| Get support [link to Askubuntu or d.u.c/community] | Talk to us: [link to ubuntuappdev -Twitter, Facebook, G+-]|

Here's a list of the current resources, for the sake of reference. In practice, we'd probably choose the most important ones and only show those in hello-unity.

General:
- developer.ubuntu.com/community

Support:
- <email address hidden>
- irc://ubuntu-app-devel (web chat available on d.u.c)
- Askubuntu (application-development tag)

Social:
- Google plus page (http://gplus.to/ubuntuappdev)
- Facebook page (ubuntuappdev)
- Twitter page (ubuntuappdev)
- Identi.ca page (ubuntuappdev)

[1]: https://blueprints.launchpad.net/ubuntu/+spec/community-q-upstream-support