Fixed small bug in the CMakeLists.txt file for the sofa library (thanks to Julien Girard who first ran into this issue).

git-svn-id: http://casacore.googlecode.com/svn/trunk@21348 6afa274c-0927-0410-9b47-a1284d797885
Improved comments
Added a test


git-svn-id: http://casacore.googlecode.com/svn/trunk@21349 6afa274c-0927-0410-9b47-a1284d797885