Add About Tab

Added a tab to provide user with information about freeseer.
This tab is the new default tab for the config tool.
The tab contains the following:

- Freeseer logo

- Short descripton of what freeseer is

- Button for freeseer help

- Button for reporting an issue

- Version number

- Copyright information

- Licence number

- Freeseer made possible by: ...

Related to #411
Merge branch 'aboutTab' of github.com:miakilborn/freeseer into aboutTab