Dialog

This is my work on the new About tab of the UI.  <a href="https://docs.google.com/drawings/d/1Y7jjzA9VmcNwwB9G8BcJ0WMrRwSbXVoDG5FNPMPKIO4/edit?usp=sharing">Prototype</a>

<b>To Do</b>
- [x] Freeseer description and image
- [x] Buttons
- [x] Button functionality
- [x] Ensure that button functionality is correct
- [x] Make image have a clear background (feasibility?)
- [x] Version information
- [x] Translations for button text
- [x] Update unit tests
- [x] Fix title of about dialog box
- [x] Fix translation problems

<a href=https://github.com/Freeseer/freeseer/pull/498>Old PR</a>

Pics
![screenshot from 2014-03-11 15 13 01](https://f.cloud.github.com/assets/6126960/2389749/8f66df0e-a951-11e3-8449-10e61e06997d.png)
![unititled](https://f.cloud.github.com/assets/6126960/2393404/9fc8e34e-a990-11e3-8bdb-817888a559dc.png)