Pull request #34: CAS-13859 Break circular dependency of casacpp modules
Merge in CASA/casaviewer from CAS-13859 to master
* commit '4ed1005bcf0d086278e748b919e447568c31e18c':
Follow more recent changes of casa6 as part of CAS-13859
updated casa-source to most recent casa6 CAS-13857 changes
Fix code for casacore changes
Set casa6 branch commit and add X11 dir
Follow changes in repository structure of casa6 as part of CAS-13859