Add atmosphere-calculator-about.glade to atmosphere-calculator.glade.


git-svn-id: http://www/svn/atmosphere-calculator/trunk@21 99022ada-cae5-4677-93e4-2780bb92de87
Add image credit line to the about dialog box.


git-svn-id: http://www/svn/atmosphere-calculator/trunk@22 99022ada-cae5-4677-93e4-2780bb92de87